The gods have been angered, and the plague is upon us.
Rit dye has changed their formula due to availability of ingredients, and it will no longer dye polycarbonates such as discs... ironically nylon based plastic such as golf balls will still dye
ALL Liquid Rit being produced has changed to the new formula.
Powdered Rit is being transitioned more slowly. Rit says only Royal Blue, Petal Pink, Fuchsia, Cherry Red, and Pearl Grey are the new formula so far, but they will all be transitioning. Black has also been reported to fail lately... so maybe they just forgot it on the list (a good substitute for black is just a long Dark Green dip).
Rit prints 5 digit batch numbers on top of the bottles, and stamps them on the bottom of boxes.
Buying Tip: Batches ending in 11 seem to be the recent stuff, so look for dye ending with 10. Nontransitioned powder colors ending with 11 should technically still work.
If you have or get dye, post the Batch Number, Color, and Effectiveness, and we can hopefully get a better idea of what will and won't work.