RECYCLING AND DISPOSING OF GLAZES
We often get the question, "What do you do with that leftover glaze you don’t want?"
Most potters, when they have a glaze they don’t like or that isn’t working for them anymore, pour all such glazes into a single bucket. These mixes are typically called “slop glazes.”
Test the slop after a while and see what glaze you’ve got. Often it is green or brown color. It may be a nice liner glaze or even a decorative glaze. Some people separate their light color glazes from their dark color glazes, or separate their food safe glazes from their non-food safe glazes.
But what if the glaze is contaminated, or you don’t have a use for slop glaze? If you are sure it has no toxic chemicals (AP non-toxic label on commercial glazes), you can dispose of it easily by pouring it down the sink (also OK for sewer or septic) or throwing it away with the trash.
Many glazes after all are just clays and fluxes. But if the glaze has toxic chemicals, or if you’re not sure if it does, the best thing to do is put it in a bowl of bisque and
fire it. This will lock in the toxins permanently. Then you can throw the piece in the trash.
If firing the toxic glazes isn't an option, call your local waste disposal company and tell them what chemicals are in your glaze, and they will tell you how best to dispose of it.