Except as herein-after provided with respect to the Removal of provisional Proof Marks on converted Barrels, if any Barrel marked as proved under the recited Act or this Act have at any Time the Mark of such Proof removed therefrom or altered, or so defaced as not to be distinguishable, or cut, severed, or removed from such Barrel in any Process of Manufacture, or by any other Means whatsoever other than the User and Wear and Tear thereof, every such Barrel shall for the Purposes of this Act be deemed an unproved Barrel.