WD-40 is a popular lubricating 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.
In this post, we list 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.
- 1) What Is WD-40?
-
2)
Where NOT to Use WD-40
- 2.1) Drive Chains
- 2.2) Door Locks
- 2.3) Hinges
- 2.4) Bike Chains
- 2.5) Garage Doors
- 2.6) RV Slide-Out Seals
- 2.7) Trailer Hitch Parts
- 2.8) Gears
- 2.9) Plastic or Rubber Components
- 2.10) Electronics
- 2.11) Firearms
- 2.12) Musical Instruments
- 2.13) As a Penetrant
- 2.14) Computer Keys
- 2.15) To Loosen Stuck Nuts & Bolts
- 2.16) As a Treadmill Belt Lubricant
- 2.17) RV (or Home) Window Tracks
- 2.18) As a Lighter Fluid
- 2.19) For Anything That Comes Into Contact With Food
- 3) Can You Think of Any Other Places Where Not to Use WD40?
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 both a company name AND 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.”
Most households probably have at least one can of WD-40 lying around!
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. Although many of us have used it as a lubricant, it’s not the best choice 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.
WD-40 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 WD-40
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 WD-40 is a lubricant, it’s not necessarily a good lubricant for many uses. It is a good dispersant and can be helpful in preventing corrosion and rust. 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.
- Designed to penetrate deeply into pins and bushing of the chains
- Excellent rust and corrosion inhibitor, as well as water resistant
- Goes on wet and sets up with a dry 'wax-like' synthetic film that helps keep your chain clean by not absorbing excessive amounts grit, grime, or dust.
- Thanks to the added Ceramic Technology, Finish Line's Dry Lube minimizes pedaling friction, repels moisture, and withstands rides up to 100 miles.
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.
- 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 WD-40 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 offers a special silicone version that’s a better choice for smooth and quiet hinge operation. It’s also extremely clean, so it won’t leave a mess on the door jamb.
- 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 to prevent rust. For best results, use an actual bike chain lube instead.
- 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...
- Goes on wet and sets up with a dry 'wax-like' synthetic film that helps keep your chain clean by not absorbing excessive amounts grit, grime, or dust.
- Thanks to the added Ceramic Technology, Finish Line's Dry Lube minimizes pedaling friction, repels moisture, and withstands rides up to 100 miles.
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.
- 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 precisely 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 used talcum/baby powder (talc – not corn starch) on our seals for years. And we still had 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.)
Important Note: Since we started using talcum powder on our slideout seals, a link has been established between talc and ovarian cancer. Please be aware of this, research it for yourself, and proceed accordingly. If you have concerns about using talc on your slide-out seals, we’d suggest wearing a mask while using it… or not using it at all. Additionally, if the manufacturer of your RV recommends an alternative method for maintaining your slide-out seals, you should follow their guidelines.
Additional Note: If you don’t have an old container of talcum-based baby powder hanging around, you should know that baby powders are now made with cornstarch and not talc. Don’t use a cornstarch-based powder on your slide-out seals. Cornstarch is unlikely to work well for this purpose, and may also clump and attract moisture. In fact, many of the recommended replacements for talc have that same problem.
If you choose to use a different powder, make sure it’s fine enough not to scratch the paintwork on the slide-out and won’t dissolve in water and just get washed away. So, if you decide to follow our method, be sure to use a talc-based powder, not corn starch.
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 WD-40 to lube those trailer hitch connections, but we advise against that. The oil in WD-40 is very light, but it does leave a slight residue behind. As we’ve mentioned, that residue can attract dust, dirt, and other debris as you drive down the road. Instead, use good-quality dry lithium grease.
- 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
WD-40 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.
- 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:
- Ultra effectiveness
- Safe and easy to Use
- 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:
- 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:
- 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 WD-40 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:
- Shoulder pain relief Heating pad for shoulder with Infrared technology, rotator cuff heating pad promotes blood circulation, effective for alleviating...
- Heat settings The heating pad for shoulders and rotator cuff is easy to use, equipped with a handy adapter that plugs directly into a wall outlet....
- Breaks Through Rust Faster Than Standard Oils: PB B'laster penetrating oil spray quickly works into rusted threads and metal parts. Ideal for...
- Loosens Rusted Parts Without Damage: This 11oz PB B'laster helps break the rust bond on frozen or corroded hardware—no cutting or force needed. A...
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.
- 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.
- 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. Although we love WD-40 for its versatility, it’s not the best choice for loosening really stuck or rusted-on nuts & bolts. If it’s all you have handy and you’re in a real bind, of course, you should go ahead and use it.
But 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!
- 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
- 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.
- Pure Silicone Treadmill Lubricant -Non-toxic and odorless, the custom formulated treadmill belt lubricant keeps your home, personal, commercial, gym,...
- Easy-to-Apply - Loosening and tightening your treadmill belt can shorten belt lifespan and cost you a fortune. Our treadmill lubrication kit can solve...
RV (or Home) Window Tracks
The original WD-40 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.
- 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. WD-40 is flammable. But 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.
- POWERFUL & VERSATILE IGNITION - Unleash the unmatched performance of Mr. Bar-B-Q Lighter Fluid, proudly Made in the USA for superior quality and...
- FAST & CLEAN CHARCOAL IGNITION - Achieve a flawless start to your grilling sessions with Mr. Bar-B-Q Lighter Fluid, the ultimate tool for quick and...
For Anything That Comes Into Contact With Food
WD-40 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. Looking to see what WD-40 is GOOD for? Read our article, “21 WD-40 Uses on Cars that You May Find Useful for Your RV!”
Free RVing Tips, Tricks, Reviews & Giveaways
As 20-year full-timers, we share everything we’ve learned about RVing over the years. Join our online community to receive a wealth of great RVing knowledge delivered daily to your inbox.
Whether you’re a new RVer or a seasoned full-timer, you’ll love the wide range of RVing topics we cover. Don’t miss a single article or any of our famous Giveaways. Subscribe to our newsletter today!
Gordon
Wednesday 13th of August 2025
Use of WD-40 on Lazy Boy furniture will boid the warranty.
Howard
Sunday 10th of August 2025
I don't know exactly when but talc products was taken off the shelf several years ago . It was linked to cancer.
James Christian
Sunday 10th of August 2025
@Howard, You can still buy pure talc from Amazon
Johnson Gregory
Saturday 9th of August 2025
Great article, badly needed. I think everyone has probably used WD40 for the wrong application. I mean, it was the duck tape of lubricants. Now the problem is that we went from one can for all to having to have 30 different bottles to lubricate our house and RV.
TheRVgeeks
Saturday 9th of August 2025
LOL! That’s true, Greg!
Nelson
Saturday 9th of August 2025
As stated, WD40 is a good sovent. I have used it to clean my hands after getting calk or varnich, etc. on them. Yes, I know, I should use protective gloves, but I am old and forgetful.
Steve
Saturday 9th of August 2025
What CAN you use it on?????
TheRVgeeks
Saturday 9th of August 2025
You can check this article out (it was listed in this post, but you must have missed it): 21 WD 40 Uses on Cars that You May Find Useful for Your RV!