Does Using Toothpaste to Clean the Car Harm the Glass?

[MacDelilah]

Toothpaste can harm the car glass when used for cleaning. Toothpaste is typically composed of many substances with abrasive properties, such as calcium hydrogen phosphate, calcium carbonate, silicon dioxide, calcium pyrophosphate, and aluminum hydroxide. These substances give toothpaste its friction function. If toothpaste is used to clean glass, under light, you can see numerous fine scratches. The correct method to clean car glass is to pour car glass cleaner into a spray bottle and evenly spray it on the interior glass. If you're concerned that the sprayed cleaner might affect other parts of the car, you can cover them with a cloth or plastic beforehand. Then, use a clean, soft towel to wipe the glass. For car glass maintenance, it's important to completely remove any dirt from the glass. The defogging and heating function should be turned off after 5 to 10 minutes to prevent the rear window from cracking. After replacing the glass, avoid washing the car for two days and try to drive on flat roads. If the wipers do not fit tightly against the glass, they can cause scratches and impair functionality, so regular maintenance or replacement is necessary. Also, regularly replace the rubber seals to prevent leaks due to aging.

[SanBenjamin]

My neighbor used toothpaste to clean the windshield last time and ended up spending over 500 bucks on a new one. Actually, those tiny particles in toothpaste are as hard as sand. The hardness of glass is only level 6, while the abrasives in toothpaste are usually level 7 or above. It might look clean after wiping, but in reality, countless micro-scratches are left on the glass. They become especially obvious under sunlight—light scatters everywhere when it hits the glass, and it’s even worse in the rain. When the wipers go over, all you see are water smears. I’ve seen toothpaste used to treat scratches on glass at auto repair shops before, but that requires professional techniques. For regular car owners, trying it themselves is just more trouble than it’s worth. Professional glass cleaners only cost 30 or 40 bucks—don’t skimp on that and ruin your car’s windshield worth thousands.

[SanLucy]

The lesson from using toothpaste to clean the rearview mirror last week was too profound. It did look crystal clear right after wiping, but on the third day when it rained, I noticed something was wrong—water droplets clung to the glass, turning it into a hazy white mess, and at night, the headlights from cars behind scattered completely. Research revealed that the calcium carbonate particles in toothpaste are harder than glass, essentially like sanding the mirror with sandpaper. What’s worse, the windshield has a special coating, and the toothpaste directly wore off this UV-protective layer. Now, every car wash takes double the time to deal with water stains. Had I known, I would’ve just bought a proper glass cleaner in the first place.

[VonAlexa]

Never use toothpaste to treat car glass. Experiments have shown that the friction coefficient of toothpaste is over five times higher than that of professional cleaners. Those fine scratches will accumulate over time into a scattering network. Especially for glass with heating wires, the rough surface can cause uneven resistance and shorten its lifespan. The worst case I've seen was a rear windshield where the owner used toothpaste to remove oil film and ended up damaging the defogger circuit. Nowadays, oil film removers on the market cost only around 40-50 yuan, containing silicone oil that doesn't harm coatings. There's absolutely no need to take the risk.