There may be a thread about this but I couldn't find it. I have been lucky over the years to find some currency. So post your finds. Find #1: Found in the street, however the bank cannot send it in as mutilated, not enough of the serial number on the right. But, I may be able to send it to the Federal Reserve for collection. I'll try -- some day.
#2: see below [I'll get this right some day] Okay, in order: Top left found while walking the dog. Top right, two pieces, found on my lawn. It must have been run over by a lawnmower. Center $1 bill. Parking lot find. Bottom: $5: Found while leaving 7-11, in the parking lot as I stepped down to go to my car. It was crumpled up and had been there for a while. $10: Also parking lot find. I forget which one.
The binary $10 is an awesome find. Yeah, the fed can take your $20 if you mail it in (it'll take forever though, from what I've heard).
Keeping up with the Joneses. I once found a wallet in a cave when I was a kid exploring. A couple of twenties and more. The notes looked like a mouse's insulation, still inside the wallet. 10 - 12 yrs old. I took the wallet to the bank's mgr's desk, and like archaeologists, we tried to find one whole serial number with it's denomination attached to no avail. But, ya, that's what he told me.
The Federal Reserve is supposed to replace your note as long as there's at least 51% of it intact. Private banks aren't necessarily required to do the same, but they usually will if it's reasonably clear enough of it is intact. If it's not reasonably easy to verify, they may turn it down and tell you to send it directly to the Federal Reserve. I remember seeing a TV show years ago (I think it might have been "Ripley's Believe It Or Not" back in the days Jack Palance was hosting it) where someone had accidentally dropped their wallet in a campfire and someone from the Federal Reserve was piecing together the ashes to see if there was enough evidence to verify what bills they had to get replacements. I'm not sure if they would still go through that much effort lol.