This is probably heresy, but how can I remove the printed decoration on a brick? I managed to buy a large number of bricks with an eye decoration cheap and found that rubbing a long time with isopropanol removed the decoration but also scratched the surface. Is there a readily-available solvent that can dissolve decorations without needing rubbing, or otherwise damaging the brick?
Brasso (yes, the metal polish) works wonders as far as removing print. Yes, you still have to rub it, but it won't damage or scratch the surface and it works fast. Just use a soft cloth, pour some Brasso on it and wipe away the print.
Also, pure Eucalyptus Oil works really well. It requires a bit of soaking, but it will remove the print wonderfully and it smells good to - unlike Brasso. Saturate a piece of cotton in Eucalyptus Oil, place it on the printed surface, let it sit for a few minutes, then wipe away the print. It may require a bit of rubbing too, but usually not much.
Hope this helps!...(c;
I tried Eucalyptus Oil a found on some figures it worked very slowly and took a lot of rubbing, while on other figures it worked on very quickly. I don't know what the difference in the figures paint/decal is or could be.
I did find that Ethyl Alcohol (not Isopropyl, have not tested yet) worked fairly quickly with aggressive rubbing with a q-tip swab.
I also notice in some cases there was a slight "ghost" impression left behind. Likely the new decal or paint would cover that though.
I got good results using Soft Scrub with Bleach, an old towel, a Scotch-Brite scrubber sponge (the green and yellow one), a bottle brush, and a pile of Q-tips.
Put a dollop of Soft Scrub on an old towel, dip the Lego piece in the cleanser, and rub 30-60 seconds on the scrubber side of the sponge. Check for results and keep rubbing until decoration is gone. Rinse well.
If there is a lot of residue buildup inside the piece or stubborn paint after rubbing, use the bottle brush and Q-tips for cleanup and detail work.
I had 60 pieces from which to remove the paint. The above method took me 1-2 minutes per piece vs. Brasso, which took about 5-6 minutes per piece.
Hand cramps are the mother of invention, I guess?