I never had any luck catching them with tweezers or foceps. However, straighten out a fish hook and tape it to the body of an old pen (or anyother inert stick like object), and suddenly you're Ahab. Happy hunting!
For the record, I only went after them when they were many inches long, and about a 1/4" wide or so. I have tons of small ones in my tank now, that I never bother with. The other night, shortly after lights out, I think I counted 13 or 14 of them that I could see at one time. Even with that many, they haven't caused any problems.
Good luck,
Chris