For the forearms you can do rice bucket (google with steven low in the search line), wrist rollers, wrist push-ups (google with gymnasticbodies.com in the search line), first knuckle push ups, push ups on fists, and theres a video online showing one of the top US gymnastic coaches wrist pre-hab series I can dig up if your interested.
Be sure to do as much (if not more) extensor work then flexor work.