Oreo - I have not tried to only remove part of a design, but I will test some ideas this weekend and let you know the best way to do that. The cast is off, and the hand is sore but getting better everyday. I have plenty of time for minifigures because I cannot use power tools or list anything heavy for four more weeks. Thanks for asking!
Shadow - Brasso is much, much faster. The example I showed took ten seconds to remove the design completely. The harder you rub and tighter you hold the cloth, the quicker it works. Older torsos tend to take a little longer, but when I first read about using Brasso, the tutorials said it would take a minute, but I have never needed that long. I usually do 12-15 at a time in 10-12 minutes.
Keep the questions coming everyone, and there will be the next installment soon!