400 coins in a day

I was detecting an old home site in a ghost town with my brother in law. I knew there had to be some coins around the place so I decided to start around front , near where the porch was. My brother in law decided to take a look at the old cellar. I was getting signals with every swing as I made my way around the front yard. The signals finally slowed down so I decided to take a look around inside the old house . My brother in law walked into the old house smiling like he does when he finds something and he reached out and placed 2 old rings in my hand. I started to swing my detector in the old house and soon had a loud signal coming from under the floor. I carefully pried the board loose and started picking up coins by the handful. By the end of the day we had found over 400 coins on that property. It took me awhile to get the coins clean as they were covered with come type of black muck. The black muck was some type hard almost rubbery material. I finally got them clean though but I noticed once I got them clean that the coins had been in a fire at some point.