My son had (as of 2 hours ago) an old Samsung Tablet (Tab-3). He was listening to music when the device got very hot. The back melted and the screen cracked. He got it outside and put it on some bricks away from the house and flooded it with water (the back had deformed enough that it came off the device. There was, thankfully, no fire.
He flooded the device for an hour, and everything cooled down, but the battery is swollen.
I called Samsung and after 45 minutes of silly questions and answers, they said to put it in a plastic bag, wrap with bubble wrap and throw it in the trash. Can't do that. On line I read things like drop it off at a store that recycles batteries (not going to do that) or take them to a hazmat center (none around here). I also called the fire dept, and they don't take them, although I thought they'd be good for training.