Float Glass Pens
Glassline Pens will work with most types of glass, from float to 96 COE, maybe higher. So it depends on what kind of “recycled” glass you’re considering. The other issue is fusing temp. Glassline pens like to be fired at 1500 F, so if you’re thinking about slumping or tack fusing they may not render the colors you’re looking for. But what the heck, it’s not a huge investment. Buy a couple and try them.