cullet

n.
Scraps of broken or waste glass gathered for remelting, especially with new material.

[Probably alteration of collet, neck of glass left on the blowing iron, from French, collar, diminutive of col, neck, from Old French, from Latin collum.]

[perh. fr. F. cueillette act of gathering, < L. collecta]  /KUH let/
broken or refuse glass used to facilitate melting in glassmaking