I hope this project is okay in the Knitting board! I didn't know where else to put it that would direct it to the right people (knitters!!)
Basically, I first tried boiling them for like 20 minutes, but that didn't melt the plastic enough. Then I got the bright idea to use my old toaster oven (one that we no longer use for food). I took the needles (Red Heart Kids needles sold in packs of 3), set the on foil (shiny side out), and baked them at about 350 degrees until "floppy" -- about a minute-2 minutes. I took them out with tongs, grabbing the black topper. I used oven mitts and shaped them around a beer bottle. I used a beer bottle because it has a smaller circumference than a drinking glass, a beer bottle is about 7.5", whereas a regular glass is about 8". I held them around the bottle for about 15 seconds, trying to pinch the ends shut. I then put them on my wrist and shaped them some more. It took me a few tries to get a non-wonky shape. I did end up melting one completely because I left it in the oven for 5 minutes. Ooops.
If you try this, please be careful and use items that you wouldn't use for food. My toaster oven is an old one, so we no longer use it for food. Also do this in a WELL ventilated area, because you don't want to breathe in plastic fumes.