I've got an old (100yrs. +/-?) Cyclops nail puller that does a great job on anything it can get the least bit of a grip on, the harder you pull the harder it grips (no hand strain required). The handle slides out to increase leverage as needed, though it has been known to generate a wee bit to much force (as evidenced in my post to the Notes and Comments board:
http://www.tfguild.org/forums/ubbthreads.php?ubb=showflat&Number=6951&page=2#Post6951 ).
