Many have buried things in their backyard. I'd did that back in the day. A guy was doing some work around his home and after churning up some dirt noticed something, "I thought they were weeds. I picked them up and just threw them aside and they went into the pile I was using for fill."
Then cha-ching popped in his head, "I got to look at the edge and it had a green tint to it and I said, 'This is money,'" also, "It looked like little mini-cigars all bound up together. As I broke it apart, I started to see what it was."
It was $1000 in small bills from the 1930's. His thoughts on why they were buried, "My sense is that something fishy happened. Somehow, somebody got new bills, rolled them up like that, put them in a jar. Somebody was hiding it, not just under their bed or in a wall for safe keeping." More here.