Mr clean, i had the same experience years back. I was in a tropical island and the thing was the size of a golf ball. We tried screwdriver, fresh water, pepsi, it still wouldn't get off. Someone even lit a cigarette, blow smoke on it, etc, all the while i was in pain. Finally i put my hand back in the sea water and it went about its merry way.
Anyway, I have been sprayed (powder blast from cyl gap) by a .357 mag from a guy in the next lane, got a scope eye from a deer rifle (pastor's), pinched by PF9 slide when trying to put it back together, Hit in the eye by the bushing and recoil spring from a 1911, etc and may more to come for sure. Just part of the game i guess.