I looked online for the best way to remove the stamps from the envelopes and they suggested soaking them in room temperature water until the stamp loosens itself from the envelope.
Here are some of the many cancelled stamps soaking. There were so many, it took me several batches to get them all done.
I then laid them out on paper towels to dry for about 24 hours. This method worked perfectly! They are all perfectly flat and clean of any envelope residue.
There were a lot of stamps, some of them even dating back to 1954. I was excited to find this little collection and looking forward to doing some craft projects using them all.