What do you do after leaving your car windows down and it rained?

Answer 1

It's probably not that big of a deal so long as you take measures to avoid mildew and mold growth inside the car as quickly as possible.

Park the car in a closed garage, preferably a heated one if possible.

First, dry it out with towels thoroughly. If any standing water was in the car anywhere, use a wet/dry vac to remove it, or use towels. Then, use mild cleaners to clean any surfaces that have dirt on them, etc., and vacuum up any debris.

Next, get a couple of fans and set them up so that they are blowing at maximum speed directly on the areas inside the car that were wet. Run these fans for at least 24 hours, ideally 48 hours or longer. This step will help make sure that mold and mildew do not grow; sometimes areas can seem dry but are actually still just wet enough to allow this growth, so using fans like this helps minimize this risk.

If after all of this you smell any mildew/must, then you may have to involve a professional cleaner or detailer to solve the problem.