For years, I have been throwing my glass shorts in a container intending to use the for something. Usually I try to use up the end of my glass rods in a bead, but sometimes I don't need to use the glass at the moment so the easy thing to do is just throw them in a jar when I finally get around to cleaning off my bench. (I'd like to add, my studio has been reasonably clean these days. Thanks to teaching.)
I threw all the shorts in a bowl of water to wash them off and soak the tags for easy removal. I used tweezers to avoid getting any cuts or splinters.
I then organized them in colors to have a variety of frit mixes. From blues, greens, transparent and opaques or mixtures. One mix looks like it will turn out to be a nice "animal print" and another of red and white for Christmas.
I placed the glass batches in the kiln set at 960 degrees. After soaking in the heat for at least 10 minutes, I then used tweezers and wore a leather glove to protect against the heat. The glass was dumped into jars of water with ice cubes. The glass quenches and fractures into little bits.
I took the glass and pulverized by hand with a muttler one teaspoon at a time. If there is too much glass, it doesn't break into small pieces. I don't recommend using a glass, it can chip, and the glass is not compatible with 140 coe glass. I just didn't have a metal glass on hand.
I placed the glass frit on paper plates and layed them out to dry. Later I poured the frit into little baggies. I plan to sift and clean the frit after getting some screens to separate the frit sizes.