Comparing rust to cancer may be clich, but it fits. Both start as tiny, largely unseen conditions that, if left untreated, will certainly spread. Depending on the severity of the case, both can be ...

Gear-obsessed editors choose every product we review. We may earn commission if you buy from a link. Why Trust Us? An ominous brown stain on the fender. A bubble in the paint at the bottom of a door.