Rust proofing guide - coupés.

Application of rust proofing compounds can be via a range of methods.  Underbody proofing can be by paintbrush or spraying.  For body cavities the best way is probably with a high pressure spray, fitted with a suitable flexible wand.  As many will not have this facility, other methods are: 1) an electric spray gun, which may also be supplied with a flexible spraying pipe for just this purpose; 2) a Waxoyl cavity spray pistol, which works from the can.  Most fluids would benefit from thinning down a little with white spirit in order to produce a fine mist; 3) just pouring in, on a suitably hot day, then driving around local roads with plenty of corners, to help spread it round inside.