Being the obstinate creature I am, I left the coins in the turpentine until now. They turned it a lovely oxide blue, and the pennies looked like absolute hell when they came out--splotched black and red and just....ick. But you know what? The &%$#@!ing paint is still on. Now, I'm not saying it looks *good* but other than the couple I had the patience to scrub so hard I think I just wore the paint down, they're still very colorful.

Right now soaking in vinegar to get all the tarnishy crud off. Tomorrow, one of us is admitting defeat.

I am perversely excited to see what they look like after being sandblasted to hell.

Deep in the harsh and uncaring desert, a caravan winding through the dunes like a delicate string of dark pearls is forced to shelter from a sandstorm. Little do they know the sleeping treasure the savage wind and shifting sands will unearth at their very feet. Copper, most ancient of metals, and beloved of the Pharaohs......

UPDATE:
Yeah, okay--sandblasting was a fairly expensive bust. But. I remembered I had a wire brush attachment for my dremel, and with a lot of patience, I can buff the paint off without wearing down the design. Then, I just have to go over it with a very fine steel wool to make sure there aren't eny weird buffing patterns. Oy.