I've watched quite a few of the videos, in the UK, where they recover all manner of interesting historic stuff, like antique swords and armour, and then in the US where they usually find dodgy used firearms and knives and shopping carts, scooters and bikes.
It's a sport with a high trash-low treasure ratio.
Which I'm kinda drawn to it but have so far resisted. While I know there's spots on the old ferry landing in Ainsworth that would yield treasures, I'm also annoyed by the things it wouldn't get - silver, gold, old glass patent medicine bottles, etc, etc.
But this might just change my thinking...