Thank you! had a totally different thought on that, Thought it was the way canadians went by piers with a big magnet, stuck it in the water and got all the magnetic coins... .01, .05, .10, .25, .50, 1.00, 2.00 etc...
There are some video's on line of some russians dredging a lake with a big 12 or so pound magnet. Pulling up 7.63 shells, coins, only big problem is no PM with regular magnet. But you can collect interesting scrap and clad i guess.
I am hoping to do some dirt fishing this weekend my self. That is if the weather holds. Have not been out much at all this year do to all the rain here in the pnw.