Having been a stamp buyer for most of my life, I can relate to the
pckaging problems detailed in this thread.
Now, as a stamp seller, I do the following:
The stamp is placed in a black crystal mount, which is then taped (by
about 1/8th of an inch) to a cardboard stiffener. The stiffener is then wrapped in an invoice so that there are no open ends, and placed in the small envelope in which the stamp has been inventoried.
But wait, there's more! The envelope is then placed in a business-sized envelope, sealed, and then the eBay
printed prepaid postage is affixed with magic-mending tape to all four sides. Finally, a three inch strip of tape is placed on the bottom of the seal.
The end result is a happy buyer and seller!