Removing concrete from cars

I’ve had more than my fair share of experience removing concrete from things that aren’t supposed to have concrete on them. I thought I’d share my thoughts:

-Concrete will damage glass, but it takes weeks.
-Lightly tapping with the rubber mallet will work incredibly well, but it will leave a dullish residue where the concrete was. You may be able to remove the residue with a cloth, or with the acid (but be very careful!).
-Be careful with muriatic acid-make sure you follow the dilution instructions carefully, and keep water handy for rinse-off. Muriatic acid will attack uncoated metal (but it takes a while). The clear coat may protect you a bit longer, but still move quickly. I’d recommend diluting the acid down, trying it, and if it doesn’t work, slightly increase the concentration and try again.
-After applying and rinsing off the acid, open the door and rinse off any liquid that got trapped in the door jam. This will prevent any acid that was trapped there from chewing stuff up.
-Gas mask is overkill, but do it outdoors-the fumes are pretty harsh.

I think the recommendation to test on a junk car is the best possible advice here.

another caution: NEVER add water to acid. It will heat up quickly and spatter all over. You must also wear safety glasses or goggles when handling acid.


I had this happen to me when driving past road construction and overspray went onto my new car. A car detailer used a clay product to remove the spots. This seemed to work well. Fortunately, the construction company payed for the process.

I ended up with concrete splashed on to a Scion xA I once owned. It was dried and I thought it would remain locked to the paint forever. I discovered a product from RoMix called Back Set which was both biodegradable and environmentally safe. It easily dissolves concrete. Here are some photos I took when I cleaned the Scion.

Hope this helps.


Use vinegar. Start with the weak acids and use stronger as needed.

Just don’t use it on a concrete driveway.