WD-40 has a number of uses around the house. It’s been a longtime tinkerer’s favorite for a reason. But it may also be one of the most frequently misused household chemicals. So here’s what WD-40 is used for, and best not used for.
WD-40’s main uses are protecting metals from water, as a penetrating oil to loosen stuck parts, and even as a cleaner. It is not, however, a very effective general purpose lubricant.
Types of WD-40
I should start with a disclaimer. At one time, there was only one WD-40. It was the iconic blue and yellow can with a spray nozzle sold for decades in the 20th century. It enjoyed tremendous brand recognition.
In recent years, lots of other products came to take on the brand name. Today, if I walk into my local home center, I can find no fewer than 12 products bearing the WD-40 brand. Unlike the original, which does 16 things and about 12 of them badly, these other products generally do one thing well. For their intended purpose, they’re perfectly fine products. I would use them without hesitation. WD-40 Contact Cleaner is a lousy lubricant, but it’s only marketed as a contact cleaner. If you use it as a lubricant, or a pancake topping, you won’t be happy with it.
If you need a silicone spray and WD-40 Silicone Spray is the only type your store carries, it’s fine. The same goes for contact cleaner or any other product bearing the same brand name. Just don’t use them interchangeably with the original formula WD-40. They aren’t the same.
And for the purposes of the rest of this blog post, I’m only talking about WD-40 original formula. The stuff my dad and grandfathers used.
What should WD-40 not be used for?
WD-40 isn’t a good general-purpose lubricant. Its main ingredient is kerosene. While kerosene is certainly slipperier than some liquids, it’s not a superstar lubricant. It attracts dirt and holds it to the surface, rather than holding it in suspension like better oils do. It also doesn’t contain the additives that modern lubricants contain. And it isn’t plastic-safe, so don’t spray it on or in things that contain plastics, especially soft plastics. It melts soft plastics in short order.
Don’t spray it on your bike chain, locks, or door hinges either. It will work, but the problem will come back quickly, requiring you to spray more of it. You’re better off using a general purpose lubricant, ideally one that contains some PTFE (Teflon).
While some people have used WD-40 as a contact cleaner or a contact enhancer, it’s not either of those either. In a pinch it may be better than nothing for those purposes. But it can just as easily do nothing or make things worse. I once read a suggestion that dousing an electric motor with WD-40 was a good way to refurbish it. I’ve tried it, and I don’t recommend it. In some cases it can make a motor work marginally better, but it can also make it worse. Sometimes much worse.
You can get proper contact cleaners and contact enhancers at any hardware store. They may cost a dollar more than old-fashioned WD-40, or they may even cost a dollar less.
What should WD-40 be used for?
WD-40 is versatile, so it’s a favorite for would-be MacGyver types. I own a can of it, so obviously I use it. But I go through it a lot less quickly than I go through other stuff. Here are things it works well on. Then I’ll follow up with some alternatives I use, and why and when I think they’re better.
Use on Tools
WD-40 is fine to use on tools. Want to put some oil on your hand tools to protect them from rust, like your great grandfather probably did? It will work fine for that. Spray some on a rag, wipe down your tools when you’re done with them, and people won’t lecture you about not taking care of your tools.
You can spray it on your shovel and other garden tools to help keep dirt from sticking to them. Other oils will work too, like cooking spray, and cooking spray might be cheaper. But if you don’t keep cooking spray in your garage, the WD-40 will work fine.
The same goes for your lawn tools, like your lawn mower. You can spray it to the underside of your mower deck to keep grass from sticking to it and help keep your deck from rusting out prematurely. But you can also use cooking oil.
Use as a cleaner
It probably seems counter-intuitive to spray oil on something to clean it. Some people would say that’s because this stuff isn’t an oil. But for certain things, WD-40 is a surprisingly effective cleaner. Just keep in mind it may very well be one stage in a multi-stage cleaning process.
WD-40 does a reasonable job of removing sticky adhesives like old tape or sticker residue from hard surfaces. Just don’t spray it on paper products like cardboard, as it will discolor paper. It can remove gum from hair and carpet, and sticky residue from your hands as well. When you use it for these purposes, follow up with dish detergent and water to remove any remaining oily residue and let it dry.
WD-40 is surprisingly effective at removing crayon. It eats through crayon like it eats through soft plastic. Follow up afterward with dish detergent or alcohol to avoid leaving an oily residue and to avoid damaging plastic.
You can also use it to remove stains from stainless steel sinks and remove light rust from tools. It can remove light rust, sap, dirt, and other residue from saw blades.
I’ve even heard of people using WD-40 to remove paint, makeup, nail polish, and scuff marks from tile floors. Be sure to follow up with a detergent with good degreasing properties afterward, like Dawn or Tide, to avoid leaving a slippery floor.
In a pinch, you can use WD-40 to soften your leather tool belt. But you’re better off using glove oil, sold in sporting goods stores for baseball gloves, since it’s specifically formulated for leather. You don’t use WD-40 as hand lotion, so I’m leery about using it as a leather oil too.
Like I mentioned above, there are better products to use for a lot of these uses. A lot of them are cheaper, too. They aren’t necessarily as versatile. But for most of the things people buy WD-40 for, there are usually better alternatives. It’s nice having a jack of all trades on the shelf, but having several things that do two things really well can be even better.
Here’s a list of things I tend to buy and my recommended uses for them:
Contact cleaner and mineral spirits
Contact cleaner is designed to clean electrical contacts and restore conductivity. Its ingredients are propellant and mineral spirits. A 12 oz can of contact cleaner costs $10 and so does a 32 oz can of mineral spirits, so I don’t spray contact cleaner on a cotton swab when I need to scrub. I dip a cotton swab in mineral spirits instead.
If you need to remove rust, there are lots of options to WD-40. Some of them are even good. Vinegar isn’t great, but it’s cheap. Specialized rust removal products tend to be better. Evaporust is a good example.
For cleaning a stainless steel sink, including removing rust, Bar Keepers Friend is really tough to beat, and it’s very affordable.
Lighter fluid and Bestine rubber cement thinner are both outstanding for removing adhesives, and they’ll even remove adhesives from paper. And unlike WD-40, they don’t leave any residue after they evaporate. I’ve removed stickers, old tape, unwanted price tags, and more with them, even off paperback book covers. Once it dries, you never know anything was there.
It’s really sold for model trains, but I use Labelle 107 oil on things like door hinges. Labelle is plastic safe, so when I need lubricant on items containing plastic, it’s my go-to. Silicone spray would also be OK on hinges. For that matter, so is 10w30. Yes, motor oil.
For locks, use powdered graphite.
On metal, when you want good lubrication without attracting dust and dirt, silicone spray is very good. I use it on the guide rails on old disk drives, for example.
I’ve had phenomenal success removing paint with generic pine cleaner. Not Pine-Sol. For some reason the knockoffs work better. Baby wipes are also very effective for removing paint. For really tough paint, the best thing I’ve found are purple cleaners like Purple Power.