All the disc burning applications I've used in Mint (K3b, Gnomebaker, DVD creator, Nero) seem to have intemittent problems with used RW discs: they can't see them, can't erase them or can't burn them. At first I thought it was a faulty drive but the same thing happens on an other machine. Disc brand doesn't seem to matter. Sometimes erasing the disc first in my dvd recorder helps but not always.
Is it just a quirk of Mint or is it that they're rewritables?