Yesterday, under the leaves in this same area were beef bones stacked. We already know to check first because the neighbors know we use the lawn mower to pick the leaves up in the street first before we sweep. They are trying to damage my mower as usual. After we removed them and cleaned the leaves there some type of white substance under where the bones were about a foot long area that we had to use boiling water on to remove. We did leaves today and the entire area was dry before we worked and when we finished.