There are three materials that are generally used for trading card storage sleeves. All three materials are acid-free and are safe for long-term storage.
- Polypropylene – used because of its inexpensive price, its high clarity and its shine.
- Polyethylene – used because it is thicker and more pliant than polypropylene. It has high clarity and is reasonably priced. Due to the thickness and softness of polyethylene, it is somewhat easier to handle than polypropylene.
- Polyester (mylar) is the only material approved by the Library of Congress for the indefinite-term storage of paper products. It is an inert material of the highest clarity. We use DuPont Melinex® or a suitable equivalent. Its stability as a storage material is the reason it is used in museums – it will remain stable for 100’s of years.
You can find our card sleeves here: https://www.bagsunlimited.com/category/540/single-card-sleeves