I receive lots of questions about the proper storage of cents and other copper coins, so what follows are my views of the subject:

1. Cardboard 2x2s. These aren't very pretty, but they won't hurt coins, even over long term.
2. Vinyl Flips. Many dealers use plastic flips for temporary storage of coins prior to sale. (Some of our coins are shipped in vinyl flips.) Vinyl flips contain PVC which will create a "film" on the coin after a couple of years. These are not recommended for long-term storage.
3. Dansco Bookshelf Albums. The plastic slides are inert, but there is a sulfur component in the paper. This album is OK for "red & brown" or "brown" coins. Not recommended for "red" copper coins, as a change in color will occur over time.
4. Eagle Holders. These are inert and safe for long-term storage.
5. Capital Plastic Holders. These holders are somewhat difficult to work with but they are excellent for long-term, storage. A substantial collection requires a good deal of storage space.
6. Air Tite Holders. Inert and safe for storage. I like these best for their good looks.
7. Intercept Shield Products. New technology created to prevent environmental damage on certified or raw coins; good range of products available. More expensive, and need to be replaced every 10 years. Very popular.

Be sure to avoid long-term storage of copper
in soft vinyl-like materials!