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Where Not to Use WD40: 19 Places That May Surprise You!

Where Not to Use WD40: 19 Places That May Surprise You!

The lubricant WD-40 is a popular product with lots of great uses. Most of us have a can or two on the RV or around the house and use it for lots of things. (It’s well-known for removing grease and adhesives, for example). But what you may not know is where NOT to use WD-40.

There are many situations where a spray of WD-40 not only isn’t your best option but could actually be harmful. Rather than being a quick solution, it can create a whole new problem… or even cause damage.

Today we’re listing out 19 places where WD-40 isn’t the best choice, and why. That includes some places you should never use WD-40. Of course, we’ll provide alternative choices better suited to a particular job.

What Is WD-40?

As we noted in detail in our post “21 WD 40 Uses on Cars that You May Find Useful for Your RV!“, WD-40 is actually a brand name.

WD-40 is an American company based in San Diego, California. “WD-40” is also the trademark of the popular product we’ve all used for decades. according to the lab book used by the chemist who developed it, WD-40 stands for “Water Displacement – 40th formula.”

WD-40’s formula remains a secret to this day. In fact, it wasn’t patented back in the 50s to avoid having to disclose the formula. (Interestingly, the European and Australian formulations are different.)

According to the Material Safety Data Sheet information, WD-40 includes the following content based on its CAS numbers:

  • 45–50% low vapor pressure aliphatic hydrocarbon (isoparaffin)
  • <35% petroleum base oil (non-hazardous heavy paraffin)
  • <25% aliphatic hydrocarbons (same CAS number as the first item, but flammable)
  • 2–3% carbon dioxide (propellant)

As you can see, WD-40 does contain a petroleum-based oil. And although many of us have used it as a lubricant, it’s not the best in all situations. In some instances, it’s not a good idea to use the original WD-40 formula at all.

Keep in mind that the “WD” stands for water displacement. This means that it’s designed to move water away, often from metals that have been exposed to moisture.

WD40 has long been touted as a fix-all, cure-all type of product. In fact, DIY lore has long held that most repairs can be made with a can of WD40 and a roll of duct tape (and a hammer?) 😂 WD-40 is great for lots of things, but it isn’t always the best, or even the right, choice. And sometimes, it’s one of the worst things you could use.

Where NOT to Use WD40

First, we want to make clear that throughout this post we’re referring to the original formula of WD-40 – the standard, multi-use WD-40 that’s been around for years and years.

We’re NOT referring to the specialized products they’ve come out with over the years that are more focused (or completely different) formulations. Clearly, the company understands that the original formula is not a cure-all, and they’ve developed other, more specific, formulations for various uses.

For example, while WD40 is a lubricant, it’s not necessarily a good lubricant for many uses. It is a good dispersant and can be useful for corrosion and rust prevention. But it shouldn’t be used to lubricate moving parts — especially metal on metal.

It’s also a penetrant. But it’s not usually the best penetrant. Ultimately, there are some situations in which you should never use WD-40.

Let’s take a look at where WD40 doesn’t perform as well as other products, and where NOT to use the original formula WD40 under any circumstances.

Drive Chains

Because WD-40 isn’t a great lubricant, it doesn’t work well at all on drive chains of any kind, including motorcycle chains and sprockets. Chain lube should also be specifically designed to avoid attracting dust, which isn’t a feature of WD-40. Here are a couple of better solutions that are perfect for your bicycle chain, too.

Sale
Lucas Oil 10393 Chain Lube Aerosol - 11 Ounce
  • Fit type: Vehicle Specific
  • Package Dimensions: 18.796 H x 6.35 L x 6.604 W (centimetres)
Sale
Finish Line DRY Teflon Bicycle Chain Lube, 4-Ounce Drip Squeeze Bottle
  • Especailly recommended for riding on or off-road in dry, dirty, dusty environments, yet it holds up well in moderately wet conditions
  • DRY Lube can also be used on derailleurs, shifters, cables, and brake pivot points

Door Locks

While you may be tempted to squirt a little WD-40 into your locks to keep them working well, it won’t do the trick. In fact, it’s also likely to do some harm. WD-40 can cause a gummy buildup, eventually preventing locks from working properly.

The best type of lubrication for this purpose is specifically designed for locks. These dry lubricants repel dust and dirt and keep your lock from building up a gunky and sticky mess. This one contains no oil, grease, graphite, or silicone.

Sale
Houdini Lock Lube
  • No oil, or silicone.
  • OK to spray around and on electrical equipment.

Hinges

Okay, we’ve all done it. Seriously, raise your hand if you’ve ever shot a spray of WD40 into a few door hinges. ✋ Yes, you in the back row, too. ✋

But, the truth is that WD-40 isn’t the best choice for squeaky door hinges. First, it really doesn’t contain sufficient lubrication to oil the hinge effectively for long. Second, although it might temporarily stop a hinge from squeaking, it can also attract dust and dirt, which won’t help the hinge work smoothly in the long run.

WD-40 does make a special silicone version that’s a better choice for smooth and quiet hinge operation. It’s also super clean, so it won’t make a mess of the door jamb.

Sale
WD-40 Specialist Silicone Lubricant with SMART STRAW SPRAYS 2 WAYS, 11 OZ
  • Use on a variety of surfaces - metal, rubber, vinyl, plastic and more. Use on 100s of items like locks, chains, pulleys, hinges, valves, cables, etc.
  • Professional- grade triple-action formula to lubricate and protect surfaces from natural elements

Bike Chains

Here’s another thing most of us have done at some point… spray a little WD-40 on our bike chain.While it isn’t likely to damage anything, regular WD-40 isn’t the right lube for a bike chain.

Specialist bike shops will surely back us up on this one. You want something that can both lubricate and prevent corrosion and rust. Due to the amount of exposure a bike chain gets from being so close to the ground, it’s especially important for the health of the chain in the longer term that lube doesn’t attract dust.

It should also contain anti-corrosion agents for preventing rust. For best results, use an actual bike chain lube instead.

Squirt Chain Lube for Bikes – Long-Lasting Lube for All Bike Chains – All-Weather Dry Chain Lube – Bike Lubricant to Reduce Noise & Chainsuck – Bike Tools & Maintenance Aid (1 Pack, 120 ml)
  • LONG-LASTING BIKE LUBE: With the Squirt lube chain wax, a little goes a long way in cleaning lumped dirt & grime in bike chains. Our bicycle chain...
  • ALL-WEATHER PROTECTANT: Whether you ride on the gritty roads of Arizona, or the murky paths of So-Cal, this wax/water emulsion will protect your bike...
Sale
Finish Line DRY Teflon Bicycle Chain Lube, 4-Ounce Drip Squeeze Bottle
  • Especailly recommended for riding on or off-road in dry, dirty, dusty environments, yet it holds up well in moderately wet conditions
  • DRY Lube can also be used on derailleurs, shifters, cables, and brake pivot points

Garage Doors

Again, the original formula WD-40 isn’t a good lubricant, and a garage door requires an excellent lubricant.

Remember, too, that garage doors often use components made of rubber, plastic, or nylon and all of these parts could be damaged by WD40.

Instead, use a product that is actually designed for use on garage doors and their components.
 
3-IN-ONE Garage Door Lubricant with SMART STRAW SPRAYS 2 WAYS, 11 OZ
  • Everything you need in a garage door lubricant: High performance and fast drying. Select a wide or narrow spray for fast, easy application
  • Lubricate and protect metal between moving parts on garage doors to keep them moving and free from corrosion

RV Slide-Out Seals

WD-40 can ultimately damage many types of plastic and rubber. It’s also important to repeat — WD-40 can attract dirt, dust, and other debris. This is exactly what you don’t want on your RV slide-out seals.

As we noted in our post How to care for RV slide-out seals, we’ve only talcum/baby powder (talc – not corn starch) on our seals for years. And we’ve still got all of the original seals on our 2005 Newmar Mountain Aire after 18 years of full-timing in it.

We’ve even got a post on maintaining slide out seals under slide toppers. Again, we use only talc-based powder. (Don’t worry – we address concerns about talc in the post.)

While we’re on the topic, if you’ve got issues with your RV slide-outs, or if you just need more information about slide-outs in general, check out our complete guide to the RV slide out.

Trailer Hitch Parts

It’s pretty tempting to grab a handy can of WD40 to lube those trailer hitch connections, but we advise against that. The oil in WD40 is very light but it does leave a slight residue behind. As we’ve mentioned, that can attract dust, dirt, and other debris as you drive down the road. Instead, use good-quality dry lithium grease.

DuPont Teflon White Lithium Grease Aerosol Spray, 10 Oz.
  • Clean, low-odor lithium complex formula
  • Enhanced with Teflon for optimal performance

Gears

Along the same lines, WD-40 can attract dust and dirt that sticks to gears, so it shouldn’t be used on gears of any type. Since there are many types of gears, and many types and viscosities of gear oils, we’ll refer you to this article from Machinery Lubrication for additional information.

Plastic or Rubber Components

As mentioned earlier, WD-40 can cause rubber to deteriorate and plastics to crack. This includes clear polystyrene and polycarbonate. For this reason, rubber and plastic components are prime examples of where not to use WD-40.

Electronics

WD40 shouldn’t be used on sensitive electronics because it contains a petroleum-based lubricant that can damage them. It’s better to use a dedicated electronics cleaner like the one below. It uses a petroleum distillate and alcohol that’s safe for surrounding plastics, evaporates very quickly, and leaves no residue behind.

Sale
CRC 05103 QD Electronic Cleaner -11 Wt Oz
  • QD ELECTRONICS CLEANER: A precise cleaner made from petroleum distillate and alcohol that is fast evaporating and leaves no residue.
  • FORMULA: With quick-drying, plastic safe, residue-free features, this cleaner is ideal for even the most sensitive electronics and will help to...

Firearms

WD-40 is not designed to clean firearms and can lead to rust and corrosion. Opt instead for a specialized gun bore cleaner and lubricant:

Sale
Hoppe's No. 9 Gun Bore Cleaner, 5 oz. Bottle
  • Ultra effectiveness
  • Safe and easy to Use
HOPPE'S No. 9 Lubricating Oil, 2.25 oz. Bottle
  • High-viscosity oil refined to perfection
  • Ideal for firearms, fishing reels and other precision mechanisms

Musical Instruments

WD-40 should never be used on musical instruments for the same reason it shouldn’t be used on firearms. Using WD-40 on a brass instrument can cause rust and corrosion. The same is true if you try to unstick keys on a woodwind instrument. If you use WD-40 on a musical instrument, you risk destroying it or at least causing costly damage.

For brass instruments, only use a premium valve oil like this one or another oil recommended by the manufacturer of your instrument:

MusicNomad MN703 Premium Valve Oil, 2 oz.
  • Pure, synthetic, long-lasting, pro-strength formula
  • Non-toxic, odorless, and petroleum free

For woodwind instruments, use only a high-quality medium-consistency key oil like this one:

Musical Instrument Key Oil for Clarinets,Flutes,Saxophones,Oboes,Bassoons
  • Medium consistency key oil
  • Maintain the key levers,the keys will be more flexible while playing.

As a Penetrant

We might say that the original WD40 is a jack of all trades but a master of none. While many people use it as a penetrant or lubricant, it really doesn’t shine at either, and can even be harmful.

Need a good penetrant? Try something dedicated to the task:

Aero Kroil Lubricant, Aerosol Can, 13 Fluid Ounces
  • Quickly loosens rusted nuts and bolts
  • frees frozen shafts, pulleys, etc.
Blaster Corp 16-PB-DS Blaster Penetrating Catalyst Big Shot Can - 11 Oz.
  • No.1-Selling Penetrant
  • Breaks Free Rusted or Frozen Parts

Computer Keys

Don’t do this! WD-40 can damage plastic and attract dust, crumbs, and everything else to your keyboard while also potentially causing damage to the components under the keys.

Instead, lightly dampen a soft, lint-free cloth with water to wipe down the keys. Then use compressed air to remove dust, crumbs, hair, and other loose debris stuck between the keys. You can finish up by using a disinfecting wipe to gently wipe down the keyboard.

Sale
Dust-Off Disposable Compressed Gas Duster, 10 oz - Pack of 2
  • Removes dust, lint and other contaminants from hard to reach areas
  • Ideal for cleaning cups, keyboards, computer mice, and workstations

You can also keep a product like this on hand for light-duty cleaning. These are great for the screens of all of your devices.

Sale
MiracleWipes for Electronics Cleaning - Screen Wipes Designed for TV, Phones, Monitors and More - Includes Microfiber Towel - (30 Count)
  • THE BEST ELECTRONIC WIPES ARE SAFE FOR YOUR ALLYOUR GADGETS: With electronics now considered as everyday essentials, it’s no surprise that you’re...
  • TV SCREEN CLEANER – Any TV screen in the house can be cleaned with their Miracle Wipes. Typical examples include Flat Screens, LCD panel, OLED, LED...

To Loosen Stuck Nuts & Bolts

Will WD-40 loosen stuck nuts & bolts? It might or might not. As much as we love WD-40 for its many uses, it’s not the best bet for loosening really stuck or rusted-on nuts & bolts.

We prefer to keep some top-tier support on hand for this purpose. We mentioned the penetrants Kroil and PB Blaster above, which can be used for this. But our #1 choice for stuck nuts & bolts has always been Liquid Wrench penetrating oil.

I grew up with a little bottle on my Dad’s workshop bench at all times. A stuck bolt would always lead to Dad reaching for the Liquid Wrench, applying a little, then tapping on the bolt to work it in. Amazing stuff!

Sale
Liquid Wrench Gunk L112/6 Super Penetrant Spray - 11 oz, Gray
  • Liquid Wrench 1 lubricant aerosol, 11 oz.
  • Solid block desiccant core: A composite of molecular sieve and activated
LIQUID WRENCH PENETRATING OIL 4 OZ DROPPER
  • LIQUID WRENCH PENETRATING OIL 4 OZ DROPPER
  • Point of use penetrant

As a Treadmill Belt Lubricant

Using the original WD-40 to lubricate a treadmill belt is a good way to destroy the belt over time. Instead, opt for a product specifically designed to lubricate the components of your treadmill, especially the belt.

Premium 100% Silicone Lube 4 Ounces for Treadmill Belt Lubrication, Easy to Apply Lubricant Oil, Suitable for Nearly All Type of Treadmills
  • 100% Silicone Treadmill Lubricant - Ideal for A Wide Range of Treadmills. 100% Silicone oil (Non-toxic and odorless), the custom formulated treadmill...
  • Eliminate Mess - Easy to Apply and No Need to Loosen Your Treadmill Belt. Each treadmill lubrication kit comes with 3 dispensing options. The...

RV (or Home) Window Tracks

The original WD40 is not a good option for use as a lubricant for your RV or home window tracks. Not only is it not durable enough, but it can also damage window components. However, the manufacturer of WD-40 has another product that works well to lubricate window tracks.

3-IN-ONE RVcare Window & Track Dry Lube with SMART STRAW SPRAYS 2 WAYS, 10 OZ
  • Quick-drying formula leaves a clear, protective lubricating film to reduce friction, without attracting dirt and debris into the tracks
  • Provides long-lasting corrosion protection against the elements, helping to prevent future repairs

As a Lighter Fluid

This one should go without saying, but since we’ve heard of this being done, we’re putting it on the list. WD40 is flammable.

And no, that doesn’t mean it makes a good lighter fluid. Using WD-40 as a lighter fluid is extremely dangerous. Use lighter fluid as lighter fluid.

No products found.

For Anything That Comes Into Contact With Food

WD40 is not food-safe. Don’t spray it on anything that will come into contact with food, such as grill grates. (Did we also mention that WD-40 is flammable?!)

Can You Think of Any Other Places Where Not to Use WD40?

If you’ve heard of other instances of people using WD-40 that could damage components or cause other problems, add your thoughts and experience in the comments section below.

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Tim H.

Sunday 13th of August 2023

Speaking of hydraulic levelers…I have one that tends to stick from time to time. I already knew not to use regular WD-40 on it, and I see below that a dry silicone lube is recommended.

Any particular brand to suggest?

Thanks for an informative article about one of my favorite all purpose products! (PS: it efficiently removes crayon from painted walls- even satin latex- without harming the paint or leaving any oily residue or stains…heard from a friend 😉)

Tim H.

Monday 14th of August 2023

@TheRVgeeks, perfect- thanks! And thanks for the reminder about the tow bar arms- I’ve probably neglected them for far too long…being as exposed to the elements as they are, they tend to be either well “lubricated” by rain or completely covered in dust during the dry runs. 😂

Speaking of which…what is your recommendation about the connection/pivot point where the tow bar arms connect at the RV hitch end? Same lubricant as the bars? Sorry about the long thread- I mean to ask about the pivot point in my first comment!

TheRVgeeks

Monday 14th of August 2023

Hi Tim... glad your "friend" knows about WD40 and crayons (😉)... it's good to know!

On the dry silicone, you could use the WD-40 Specialist Dry Silicon linked above under #3... or really any dry silicone spray. We have a can of Roadmaster Silicone Lubricant we use on our towbar arms, so we use it anywhere dry silicone is the best choice.

Scott Floyd

Saturday 12th of August 2023

Excellent reminders. I just purchased the correct items after reading your post. Thank you

Steve

Saturday 12th of August 2023

Do not use WD-40 (original) to lubricate hydraulic RV levelers, tow bars, steps or TV antenna lift mechanism. Chain wax is good on steps, dry silicone on towbars and levelers.

Mary Bennett

Saturday 12th of August 2023

Thanks for this! I clearly should not be using it to lubricate my sewer pullout valves but I have (and it helps, but now realize long term it will hurt). What should I use for those??

Mary Bennett

Monday 14th of August 2023

@TheRVgeeks, thank you!

TheRVgeeks

Saturday 12th of August 2023

Hi Mary. Ideally, you shouldn't need to use ANYTHING for your sewer valves. If they're sticking and/or difficult to open/close, it's usually a sign that they're aging and need to be replaced (RV Gray Valve Repair — REAL-TIME DIY Holding Tank Valve Replacement). When you DO replace them, you can use a pure silicone grease (like this, available on Amazon: https://amzn.to/3KE8Sst) on the O-ring gaskets that seal the blade valve to the valve body. This will keep the blade sliding smoothly. The silicone shouldn't do any damage to the O-rings. And since silicone isn't water soluble, it'll stay put for a good length of time, keeping things sliding easily.

Vince S.

Saturday 12th of August 2023

Of course there’s better specialty lubricants, water dispersants, penetrants and solvents on the market but most RV’s lack the space to carry dozens of cans, bottles and jugs of specially formulated blends to accommodate the myriad of applications they’ll encounter. WD-40 has never been known to cause rust but not using it sure has.

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