I'm guessing that these Statler and Waldorf heads are from Muppets Tonight. At least from the mid-late 1990s era.
At this time whenever people find things like this, I don't know why people can't just donate them to the Jim Henson / Muppet exhibits at the museums.
The Museum of The Moving Image, Center of Puppetry Arts ( Atlanta, GA ), Smithsonian, Birthplace of The Frog Museum in Leland MS, or the traveling Jim Henson exhibitions.
It just makes sense for someone to do that.