Meguiars advises that some ash residue when mixed with water can form a substance similar to drain cleaner that eats away at a car's exterior. For those of you unfortunate enough to be experiencing ash fall from the fires burning in California Meguiars recommends that you keep your vehicles in a garage if possible; close windows and sunroofs; use a fitted car cover; wash and dry your car every night until airborne ash subsides; and wash away any residue after the fires die down.
[Source: Los Angeles Times]
