old hot water heater

Spent last 3 days installing new tankless hot water heater(a read itself). My question is what to do with the old. Bud and I discussed it and thought maybe test the ad run on tv about exploding water heater, wife already saying to dangerous, but thought the same for my basketball cannon, sh#t she's probably right.

I always set my old water heaters at the curb. And theyre gone in no time. Old water heaters are gold mines for the scrap metal collectors in my neck of the woods. :)