I was looking at this stuff called PROS AIDE for mixing with airbrush paint so I could paint my friends predator silicone bodysuit but at the time I had no money to get the stuff so haven't tried it but its what the cosplay and mask/sfx peeps use.
Lee
A note on this: If you want to spray pros-aide, get a bottle of Isododecane. You can find it from cosmetic ingredient suppliers like TKB Trading. It dissolves pros-aide a treat, so if your airbrush gets all gummy, it'll help. Pros-aide is an acrylic emulsion used as an adhesive for prosthetics, FX appliances, etc, and what's sold as the remover for it is a mix of isododecane to dissolve the pros-aide, and alcohol so you don't feel all greasy. They're a bit marked up though.
If your airbrush contains silicone parts (o-rings? seals?) don't soak in isododecane, because I've seen how it dissolves silicone resins and I imagine elastomers might swell in the stuff.
Most importantly don't let the stuff linger in your brush! Pros-aide is tenacious! If it can keep a wig and a lion nose stuck to my face for a whole day of convention attending, imagine what it will do in your airbrush!
Funny story that was told to me by a makeup artist/salesperson at Kryolan: He had a customer come in, who had coated himself in pros-aide and glitter (like a self inflicted tarring and feathering, but far more glamorous) and found himself unable to get the stuff off. He had tried everything, including scrubbing the glitter and glue off, but nothing except the correct solvent worked. It's that strong.