I hunted a couple of old bedrock swimming holes in locale of old mining operations. I was and still am almost certain these holes have been used by miners in the late 1800s/ early 1900s. Came up with a lot of modern coins, and someone's iphone 6 (still drying in a bag of rice). Hoping to get out for some more creek hunting this July.
I am still stressed out about a coin ping through some bedrock. I found the crack that it slid under, and after washing out some silt, there is a small hand-sized cavern back under the bedrock. The coin is about 4 inches around a corner that I can't reach. I was afraid I would get my hand stuck if I really went for it, so I left the target behind. I think I will return with some sort of reacher or brush to see if I can pull it out. Could be a 2000s dime or could be a silver dollar. The curiosity is killing me on that one. I'll have to get some photos of this situation.
Andrew C. it sounds like you need to make a Slurp Gun. You can make them as complicated or as simple as you wish, but basically all it would be is a tube with a plunger that you can draw back quickly to create suction.