A better idea. Use aircraft grade paint stripper and paint with that. Then use moly-lithium
wheel bearing grease so they have to degrease the walls in order to repaint them. If the
stripper does it's job to the fullest and the porous stone absorbs the grease, they'll be at it
for days. I've used tal-strip to remove the paint off a car hood. It took it down to bare metal
in 10 minutes and the steel started to oxidize 12 hours later.
All of this can be found at your local auto parts store. I know, because I work for one part
time.
:D
@cpt99117733
My friends and I used to give ourselves tatoo's with that stuff. We snagged it from the art
class. I'm not sure if it would work on that thick glossy crap they use in bathrooms though
because it's not porous enough.