I have several jars of some commercial glazes, that were left from a previous teacher. I kept them around for a few years, but they aren't very popular, with my students. I am also not sure, whether or not they are food safe, which may be one reason, they don't get much use. I do know, because of their labels, they have things like soluble copper and cadmium in them. So I'm fairly certain that I shouldn't just throw the glaze in the trash, or wash it down the drain.
I've seen people here recommend that similar toxic elements can be fired, to make them inert, then disposed of. So I was thinking of going this route.
I made a large bowl, for this purpose. My question is, does this seem like a good method for disposal? Second, most of said glazes have become caked in the jars. Can I just dump and/ or crumble several of the cakes into the bowl? In other words, is there such a thing as too much glaze inside the bowl, in this case? I just don't want the glaze to crack the bowl, during the firing and leak all over my kiln.