Personally, I prefer to use a box wrench. Less chance of rounding, and it stays in place on the bleeder during the open/close/open/close routine. I always attach a hose to the bleeder nipple, so adjustable wrenches, pliers, etc. just don't fit.
Anyway, I found this place "brakesconnect.com" that has bleeders, washers and other components. I ordered a couple of bleeders -- hopefully I can replace these silly buggers.