One unorthodox treasure hunting method I once performed as a kid was going to thrift stores and sitting on all the donated couches. I pretended to be interested in buying them but in reality I would just put my hands under all the cushions and take all the money hidden beneath. I did this once a week (so there would always be new couches to check). And I always would leave with at least $2-$5 in coins. Sometimes I would find random things - like remotes, flash drives, DVDs, and lots and lots of crackers and chips.