Isn't that a great word? Mudlarking... When I was reading The Sea Glass Hunter's Handbook by C.S.Lambert, she explains about mudlarking.
It's a term used for riverbank beachcombers in England. In the 1800's, scavengers of all ages would explore along the Thames River among the barges, looking for anything they might be able to sell to help them survive.
Coins, metal, crockery, glass and valuable artifacts have been found in the Thames. It can be very dangerous due to the 16 foot -23 foot waves of the incoming tide. ( Not to mention the raw sewage.)
Personally, I think I would rather stick to searching for sea glass on the beach, and maybe, crawling over or around a few rocks!