This isn't really a detailing question nor a service question... I don't think. But here it is anyways! I HATE rust! I need my car to last since the economic blah blah blah has pretty much killed my business. So my question is do you and if so what do you use to spray the underside of the car to prevent rust? I have been told cosmoline, wd40, trans fluid and trans fluid mixed with wd40. If you have done this what did you use and how messy is it? Did it work? I know there is a rust warranty but BMW's version of rust (perforation) and mine (smallest bubble) are very different! so help me out fellow members! I would like to know what you use and how it works out! Thanks Damien PS the bottom two answers in the poll are just fun. If you do vote could you explain your vote a bit? Thanks!