Lots of people talk about using it, but there are very few pictures of the process/results, so I figured I'd make some:
You can find the stuff at your local grocery store with the cleaning supplies like Windex, 409, etc.
Scrub a dub, dub, ugh, smells like a dead bug!
Oooh, shiny and clean! :D
Took a bit of effort, about 10 minutes worth of scrubbing with paper towels and multiple applications of the stuff, but it paid off, completely took off the paint without damaging the plastic at all.
Probably good it didn't come off real quick, cause if it did the plastic probably would have wound up all scratched up.
This was a great piece to test it out on cause Lego has never produced a plain black one, only black ones with ugly printing. Next I plan to test it out on some of those new circular 1x1 transparent tile pieces that come with those new Ninja sets. They all have goofy/ugly printing on them and as of yet they don't make them without it, so they're good candidates...although there might be a trans-green one in one of those new girly sets...can't remember.