I've heard this being discussed before, "DVD rot" is those milky/cloudy looking spots that appear on the playing surface of some DVD's. Some of the DVD's I own have this problem, fortunately not too many of them, although the DVD set I have of Space 1999 from A & E has the "DVD rot" problem pretty bad and most of the discs have those nasty looking spots on the playing surfaces. The discs still play but my concern is the discs might eventually stop playing because of this issue. Does anyone know what causes this "DVD rot" to occur? Are some studios using poor quality DVD media? I take care of my DVD collection and keep the discs in a dry location but occasionally some discs develop those nasty looking spots which is not good.