1971 S Kennedy Half Dollar

Yes it is, Nice find.

Yep, that would be a proof although it would be considered an "impaired proof" since it has seen a small bit of circulation. The coin could probably use a dunk in acetone, it may not remove all of the fingerprint-related haze but at least any active contaminants would be dealt with.

Acetone is a volatile organic solvent that is inert with respect to coinage metals. It will remove surface contaminants such as fresh fingerprints, greases, PVC residue, etc but it will not remove toning or stains. The usage of acetone would fall under the category of "coin conservation" vs "coin cleaning" since cleaning is typically used to describe a process harmful to a coin.

Acetone can be found at most any store that has a paint supply section. I would not advise purchasing it for just this coin though because you would probably have to purchase at least 1 quart of it and that would cost more than an unimpaired proof. Because it is flammable and volatile, you do have to take some precautions when working with it but it can be relatively safe to use.

I have been searching rolls of Kennedys for awhile now and still haven't found an "S". Congrats Marc115028.

Upstate thats a question I think everyone here asks themselves. I'm always surprised about the coins that people find. I've found 3 nickel proofs in roll's from bank at work. I think my best find was a silver 1976 Kennedy half dollar. Someone must have broken it out of set.