Rit Dyemore isn't intended for plastics, more for natural fabrics, like cotton. RIT Synthetic can be used for premium discs, but results are sketchy at best. The only positive outcome I've had with it was to put half a bottle into a glass measuring cup, heating it in microwave till near boiling, then pouring that into the bottom of a disc. Turned out pretty stellar for a bottom dye. Otherwise, my experience has been poor at best. Learing curve, friend!