Cheryl,
If you put it into the mix it may disappear.
You could use it as an 'overlayer' brushing the outside of your item with bonding agent and patting the crystals of color on.
Dena

Glass dust is just silica, like in sand, so if you just want to recycle your dust, it will mix up just fine. Dena is right, it will never show but the grinder dust usually isn't a pretty sight anyway. Mine always looks muddy from all the colors. I imagine if you had alot of it and you used it in place of sand, sifted and pulverized all your other ingredience, you would have a very fine mix for casting. Let us know how it goes.

Jo