I have suspected that the playfield glass on one of my games was plain plate glass and not tempered safety glass for a while.
It was too sharp and not rounded on the edges. It had a few chips along the edges. When I tried to see "waves" in it with polarized sunglasses, I could not see any.
But it was in pretty good shape with only a few minor scratches, and I didn't feel like replacing it unless I had to.
I finally got paranoid enough to replace it.
Since I didn't know if it was tempered, I wanted to get rid of it instead of keeping it as a spare.
I took it out into the driveway, put it inside a thick plastic trash bag, and gave it a single light tap with a hammer.
(Wearing long sleeves, heavy gloves, and safety glasses. I'm not THAT stupid.)
It broke into multiple deadly sharp shards.
I am so relieved that did not happen accidentally while I was working on the game.
The shards basically shredded the durable trash bag. So happy that was not my fingers or other body parts.
PLEASE get rid of any glass that you are not sure about!