Injection marks?

White glue applied in even coats until it is just above the pin mark , then rub away with a cloth and warm water. no mess, no solvents, and if you goof up the white glue just comes out with water.

In situations with tight clearances, it depends on the exact nature of the problem. Sometimes, I'll use an Exacto blade as a scraper. Depending in the type blade used, you can cet into some awkward areas. Sometimes, I'll superglue a tiny spot of sandpaper to a toothpick. Sometimes, I'll use a tiny dab of putty and work it with the end of a toothpick as it dries. Sometimes a drop of superglue, if carefully applied will go where it needs to go and no require sanding.

I use this method it seames to wrk great for those nasty spots.
http://www.finescale.com/fsm/community/forum/topic.asp?TOPIC_ID=33592

The pics are gone but the directions are there.