<alcohol. Now I'm just soaking the heads in a glass in the alcohol, and <waiting overnight to see if they'll then come clean. If that fails, I was <wondering about a toothbrush with just 91% alcohol. NO! Try a Qtip with some acetone (nail polish remover) and then clean that off with isopropanal. There are plenty of more aggresive cleaners before resorting to abrasives. When my RL02 crashed (bad pack) I had to use MEK on the heads to get them clean. Isopropanal or ethanol are about the most mild solvents and someof the media binders need some push. Allison