Ive clipped the glassine envelope  to make sure they were not attached to the envelope.

The Hollywood Official Stamps of the Stars Sheet ' Y ' is an original sheet featuring official stamps of stars from the movie industry. Made in the United States, this sealed sheet contains authentic stamps and is a unique collectible for movie enthusiasts. With no modifications made to the original product, this item retains its authenticity and value as a piece of movie memorabilia.