I am using magicsculp, or you can use Aves.
I have modifed and even made some of the arms on my USMC Mt. Suribachi figs, and always use my magicsculp and a wet finger to fill in the seams on my resin figs both big and small.
A great investment that really does cut down on all the problems associated with using things like contour putty or green stuff.
HTH
David
Build to please yourself, and don't worry about what others think!
TI 4019 Jolly Roger Squadron, 501st Legion