Thanks guys, this is a lot of great advice for me. I really appreciate it.

- I'll look for Bondo spot putty at my local hardware/auto store. Might be worth a shot.

- I have 90% alcohol which I might try. If that doesn't work I'll give Simple Green a go.

- The primer I used is "Vallejo Surface Primer" â€"and I did wash the sprues before assemblyâ€" but obviously I need to give the built parts a wipe before painting. My hands were all over it and maybe there was oil transfer.

- It was airbrushed at around 20PSI, but maybe I need to lay down a thinner coat and let that completely dry overnight before attempting anything else. It had been a good two hours before I started adding in putty but it looks like I was too hasty.