OK, kidding! I used BS (hmm...) to get some abrasive effect, liking that it sort of "melts" when saturated and theoretically wouldn't be too harsh, and would be easy to remove (plus, that's all it is, just BS - no other ingredients that may be left behind). The matchbook striker sounds pretty harsh by comparison but I'll have to give that a try, too (gently). Thanks for passing on the idea, I hadn't come across it before.
Scott
Scott