WD-40 is a household staple, but even this versatile spray has its boundaries. Misusing it on the wrong surfaces can lead to damage, safety hazards, or expensive repairs.
Before you grab the can, learn about these 10 places where WD-40 should never be used—and avoid turning a quick fix into a costly mistake.
1. Door Hinges
Despite seeming like an obvious solution for squeaky doors, WD-40 provides only temporary relief for noisy hinges. The product lacks sufficient lubricating properties to provide long-term smoothness, and its cleaning solvents can actually remove existing lubricants from the mechanism.
The spray also tends to attract dust and dirt, which can accumulate and create unsightly black marks around your hinges. Over time, this buildup can cause more damage than the original squeak you were trying to fix.
2. Vehicle Brakes
Using WD-40 on brake components is extremely dangerous. The lubricant reduces the essential friction needed for proper braking function, which could lead to brake failure and potentially fatal accidents.
When applied to brake systems, WD-40 can compromise your vehicle’s stopping power, especially in wet conditions. If your brakes are making noise, it’s a sign they need professional servicing rather than a quick spray fix.
3. Electronic Devices
Spraying WD-40 on electronic equipment like phones, tablets, or gaming controllers can cause severe internal damage. The product can seep inside through small openings and corrode sensitive components.
Additionally, using WD-40 on electronics will likely void your warranty. The spray’s solvents can break down protective coatings and damage plastic casings, leading to expensive repairs or complete device failure.
4. Clear Plastics
Polycarbonate and clear polystyrene plastics react poorly with WD-40’s chemical composition. This includes items like eyeglasses, lighting fixtures, and greenhouse panels.
The spray can cause these materials to crack, cloud over, or become brittle. When dealing with clear plastics, it’s best to use specifically designed cleaning products rather than risk permanent damage.
5. Bike Chains
While WD-40 might temporarily quiet a noisy bike chain, it’s not suitable for long-term chain maintenance. The product’s cleaning properties can remove necessary lubricants from the chain mechanism.
Professional bike mechanics advise against using WD-40 as a chain lubricant. While it might be useful for cleaning a dirty chain, you should always follow up with proper bicycle-specific lubricant.
6. Food Contact Surfaces
WD-40 is not food-safe and should never be used on kitchen equipment or surfaces that come into contact with food. The chemical compounds in the spray can be harmful if ingested.
Even trace amounts left on surfaces can contaminate food preparation areas. When fixing kitchen appliances, restrict WD-40 use to non-food-contact areas and thoroughly clean any overspray.
7. Locks
Door locks require specific lubricants to maintain proper function. WD-40’s degreasing properties can remove existing lubricants from lock mechanisms, potentially making the problem worse over time.
The spray might provide temporary relief for a sticky lock, but it can attract dirt and debris that will eventually cause more serious issues. Instead, use a graphite-based lubricant specifically designed for locks.
8. Waxed Surfaces
WD-40 can damage waxed furniture and wood finishes by softening or completely removing the protective wax coating. This can result in permanent damage to the appearance of your furniture.
The spray’s solvents can strip away years of careful maintenance, potentially requiring complete refinishing of the piece. Always test any product on an inconspicuous area first when dealing with finished surfaces.
9. Hot Surfaces
Never use WD-40 near heat sources, as it is highly flammable. The spray can ignite when exposed to hot surfaces like engine parts or exhaust systems.
The aerosol can itself can explode if exposed to high temperatures. Always allow engines and machinery to cool completely before applying WD-40, and keep a fire extinguisher nearby when using the product.
10. Open Wounds or Skin
Direct skin contact with WD-40 can cause irritation and dryness. The product can be particularly dangerous if it enters the bloodstream through cuts or abrasions.
This may happen it you’re working on a car while using WD-40, and may not even be aware you have an open wound.
Always wear protective gloves when using WD-40, and wash any exposed skin thoroughly with soap and water. If skin irritation occurs, seek medical attention promptly.
While WD-40 remains an invaluable tool for many maintenance tasks, using it appropriately is key to avoiding costly mistakes or dangerous situations. When in doubt, always consult product manuals or seek professional advice before applying any lubricant or penetrating oil.
Don’t Miss These:
Davin is a jack-of-all-trades but has professional training and experience in various home and garden subjects. He leans on other experts when needed and edits and fact-checks all articles.