Great post. Made pretty much every point I was going to make, but put it much more elegantly. Also, as a few others have said, I wouldn't worry about it too much OP. Smoke it in a bong or somethin' if you're worried, but I've smoked glass before and had no issues (not that I would recommend it!) /edit: SharpStones aren't hyped up, they just make a great product for a great price, leaving their customers happy
did u try a magnet to test if they were really metal in nature. magnet may also be a good way to purify weed of any metal shavings found within. careful magnetic extraction is required
What above poster said. Anybody who makes QWISO will tell you that you need to filter your produce properly before placing it in the evaporation tray.