NucMed-I think Monogram has ownership in a couple of companies that manufacture putty (just kidding).....Your P-61 looks great-that is an interesting plane.
silentmodeler-as far as the chipped paint effect, I remember an FSM article where the builder painted the model silver, allowed to dry, then sprayed a coat of Future. After the Future was dry, then the final color, allow to dry, (but not completly) and then take some low-tac masking tape and 'dab' the surface, pulling off the last coat. Also, I saw a builder paint the silver, then when dry (not sure if it was Futured), apply rubber cement where he wanted the chipping. Then the final coat, allow to dry, and remove the rubber cement. If you have already applied the final coat (and you have), then a silver pencil is a good option for light chipping. Not sure of a good way to do heavier chipping/pealing though....
btw-your Kate is looking good. I'm starting on the Tamiya Zero (drilled out the seat and primed the interior bits) and I'm thinking of doing the chipped paint effect too-I'll be watching to see how yours turns out.