Thanks, Larry. I had never heard of Xylene and neither had the local shlub at Home Depot - but I found some and it worked well for removing those ugly purple stains. (If you're just tuning in - beware, it eats through plastic & PVC so don't use it to clean the stains off of PVC pipes.)
The stuff is amazing - I can't wait to see what else I can clean with it - miracle solvent/elixir. (I wonder how it tastes...)