Is that just a regular eraser? Erasers work pretty well to remove things like that. They are abrasive though, so they can remove more than just a stain however. Mr. Clean Magic Erasers are supposedly very abrasive and a bad idea in most cases.
For some marks on some figures I will use sanding blocks meant for manicures. They come in a variety of abrasive levels, some are really abrasive and some barely feel different from smooth. If you go this route, try an eraser first, because if an eraser does the trick, don't sand paint marks off your figures.
Last Edit: Mar 21, 2018 11:18:11 GMT -6 by Branjita