Marker on Marker

I learned something rather random and fascinating today. My job involves organizing library items, including CDs. Normally, I would work on another project during my hours "off-desk", but today I started to help out with updating CD labels. I was shown how to erase the fine-tip permanent marker ink from the CD: loosen it up with a dry-erase marker, wipe off the dry-erase residue, then all of the marks from the marker come off easily! I had never seen that happen before. Well, I had, but it never really clicked in my mind until today. Use a marker to erase another marker? Cool! I am grateful for this small "Aha!" moment.