I've recently come across a great technique!
I can't take credit for it, so want to draw your attention to JinSaotome. He's a fellow customiser, and chances are that if you've found me online, you'll know about Jin. He's considered one of the greatest action figure customisers.
Anyway, I like to be a bit experimental in the techniques I use, but Jin came up with a great technique that I'd never have thought of: http://www.angelfire.com/mech/jinsaotome/WorkspaceSetup/GapFill.html
This is saving me a lot of work when getting rid of engraved details on figures. As Jin says, this technique is great for those times I don't want to wait over 3 hours for putty to cure.