Seven Places You Should Never Use WD-40
WD-40 is designed to prevent rust by driving water out of cracks and crevices in metal (that’s what “WD” stands for). It is also a multi-purpose lubricant and can even be used as a solvent, but there are places where it should never be sprayed.
WD-40 does not have the same viscosity as traditional grease or oil and may attack certain coatings and may also cause problems when used as a replacement. While it’s tempting to think it’s a good idea anywhere you need to reduce friction, here are some places where you should definitely never use WD-40.
Do not use WD-40 on plastic.
If you’re trying to lubricate a sunglass hinge or remove a price tag from the surface of a plastic container, you may be tempted to reach for the can of WD-40… but never use the clear plastic surface or polystyrene or polycarbonate plastic.
Products containing styrene, which are typically classified as number 6, include things such as toys, disposable cups and cutlery, and appliances such as smoke detectors. Polycarbonate, known as No. 7, can be found in kitchen appliances such as refrigerators, clear packaging, plastic lenses and protective gear. Because of WD-40’s chemical composition, it can damage plastic and ruin things like sunglasses with plastic lenses. When in doubt, it’s best not to use WD-40 on plastic.
Do not use WD-40 on wood.
WD-40 can dissolve wax coatings. If you use WD-40 for cleaning, keep it away from wood floors and furniture. Because wax creates a waterproof barrier that protects woodwork from water damage, it’s best to leave the wax where it is. Additionally, since WD-40 can penetrate into the grain of untreated wood, it is generally not recommended to use it on any wood surface, not just waxed wood.
Do not use WD-40 on natural stone.
Since WD-40 works well for many cleaning tasks, you might be tempted to try it on stone tiles or countertops. But natural stone is porous, and you shouldn’t use WD-40 to clean it—WD-40 can soak into the surface of the stone and stain it. Additionally, many stone surfaces are treated with a wax polish and WD-40 will dissolve the wax coatings.
Do not use WD-40 on surfaces where you cook food.
Some appliance manufacturers recommend using WD-40 on stainless steel, but you should never use WD-40 on surfaces that will come into contact with food. While streak-free shine is a powerful motivator, it’s clear that WD-40 should not be used. and while occasional food contact is not a big deal, surfaces with which food is in frequent or prolonged contact should never have WD-40 on it.
Do not use WD-40 to clean electronics.
Never use WD-40 on electronics as it can react with some plastics and attract dust and other particles. If WD-40 gets on your smartphone or laptop, it can not only damage the screen, but also ruin buttons or penetrate internal components. It is best to use a cleaner specifically formulated for electronics.
Do not use WD-40 on bicycle chains.
Although WD-40 is sometimes used as a replacement lubricant, it is not a good replacement for bike-specific lubricant. It does not have the right viscosity to be used as a chain lubricant, and dirt and fibers can stick to it over time. While you can use WD-40 to clean a bicycle chain, it is not recommended to use it as a lube, and if you do decide to use it to clean your chain, you should reapply your regular chain lube afterwards.
Do not use WD-40 for arthritis pain.
This should be obvious, but it unfortunately needs to be said: despite strong claims to the contrary, WD-40 will not help relieve arthritis pain or creaky, stiff joints. While there are many ways WD-40 can help lubricate parts, your joints won’t react to it the same way they would to a stuck bolt. Human bodies definitely don’t use the same lubricant as engine parts, and medical professionals don’t recommend using WD-40 to treat any medical conditions.