Currency collecting is much like coin collecting, but with added pitfalls. In coin collecting it is possible to damage a coin, but it is so much easier to damage currency.
Currency is valued by its scarcity and its condition. Among the things that devalue currency are damages corners, folds that cause creases, and holes, including pinpoint holes. Another problem is currency is occasionally written upon. Since wallets usually fold, damage by normal usage is common.
Finding crisp bills is difficult, and preserving them in crisp condition is important when they are part of a collection.
Plastic is petroleum based. However, paper requires trees, and the rest of the tree not used, leaves for example, decompose and return carbon dioxide to the atmosphere. The reason for plastic, and we are talking of paper thin, flexible plastic, is durability. Also, tree removal decreases the albedo of the planet, allowing heating up. Soil has lower albedo than green leaves or needles.
The currency collectors I know seem to think the U. S. will be making the change, but when is not known.
Metal storage is probably available, but costly, since they exist for trading cards. Metal is not an environment solution, since metal takes heat to smelt from the ores, and energy to mine. Weighing environmental damage is difficult. And, deciding which environmental issue is best to opt for is another matter, since runoff into waterways is another form of damage. It then becomes a question of air or water that is being dispoiled.
blackspanielgallery, Thank you for practical informations (uniformly enlightening but especially so about error bills and fractional currencies), pretty pictures and product lines.
Aren't plastics largely made from fossil fuels or is plastic bill-making free of fossil-fuel chemicals? I wonder if the United States will consider abandoning paper at some time, what with scary United Nations reports about damaged soils and decreasing numbers of woody plants.
Would sleeve-storing boxes ever be made of metal or would they only be of perhaps some kind of cardboard?