Gasoline stains and Rust

Here is what I do on Motorbike Models, I use Clear Yellow (maybe add a tiny bit of clear orange) to stain the crankcase where normally petrol drops of the fuel tap(common on older bikes).

Rust there are many methods from buying products like rustall to actually using rust and so on.

A coat of Future on top of the base coat will solve the problem of the wash reacting with it.

For rust, get a small Brillo steel wool pad, used for cleaning in the kitchen. Soak it in Water until it rusts. For newer rust, pull it early when the rust is orange, for older rust, wait til it's more brown. Once the rust is the color you like, crush the rusted pad into powder. Voila! Your very own rust!

To apply over surfaces, you can brush the powder straight on, then seal it with a dullcoat. For 'running' rust, mix some of your rust powder with a mix of 50-50 water and white (Elmer's) glue. Dip a brush into this, and then place it on the model where you want it to run and let it run down the sides. Once it's dry, you can seal it again with a coat of dullcoat.

Hope this Helps!

Thanks for the replys....they all sound great!