I stripped five Weaver E8s.
With one A-A set (factory painted SP 'black widow') one of the units stripped almost completely in 91% alcohol over 2-3 hours while the black on the other unit took three days to loosen. Even then it required hard scrubbing with a toothbrush to get it cleaned up.
On another A-A set (I'm pretty sure it was factory painted NYC lightning stripe) it took almost a week to get the paint off.
Don't give up it eventually comes off.