How to Store Paper Money Properly
Paper money degrades from four things: acid, plasticizer, humidity, and light. Every one of them is avoidable, and the cost of doing it right is a few cents per note. The cost of doing it wrong is permanent.
The single most common mistake is storing notes in soft flexible plastic. It looks fine for years and then the note is ruined.
Quick facts
- Use
- Mylar, polyester, polypropylene, or polyethylene sleeves
- Avoid
- PVC, vinyl, soft flexible plastic sleeves
- Humidity
- Keep between 35 and 55 percent
- Light
- Store in the dark, UV fades ink permanently
- Never
- Tape, staples, paper clips, lamination, or folding
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The PVC problem
PVC sleeves contain plasticizers that migrate out of the plastic over time and onto whatever is inside. On paper money the result is a greenish sticky film that bonds to the surface and cannot be removed without damaging the note.
The tell is flexibility. PVC sleeves are soft and floppy. Archival sleeves made of Mylar or polypropylene are stiffer and make a slight crinkle. If a sleeve feels soft and rubbery, take your notes out of it today.
Environment
Humidity above about 60 percent invites mold and foxing, the rust-colored spotting that appears on old paper. Below about 30 percent the paper becomes brittle and cracks at the folds. Somewhere in the 35 to 55 percent band is right.
Attics and basements fail on both temperature and humidity swings. An interior closet in the living space of the house is usually the best storage a collection will get without a dedicated cabinet.
Handling
Handle notes by the edges, with clean dry hands or cotton gloves for anything valuable. Skin oils transfer and show up years later as darkened areas.
Never repair a note. Tape yellows and bonds permanently, and a taped note is worth a fraction of the same note untaped. Never trim edges to tidy them, and never press a folded note flat. Graders detect all of these and label the note accordingly.
Before you do anything else
- Buy sleeves rated archival or acid free from a currency supply dealer, not generic plastic from a stationery shop.
- Store notes flat rather than upright, so the paper is not supporting its own weight along a single edge.
- Keep a simple inventory with photographs. It matters for insurance and for your heirs.
- For high value notes, a third-party grading holder is also the best long-term storage available.
Frequently asked questions
What is the best way to store old paper money?
In archival sleeves made of Mylar, polyester, polypropylene, or polyethylene, stored flat, in the dark, at moderate humidity between 35 and 55 percent.
Can I store banknotes in plastic sleeves?
Only if they are PVC free. PVC releases plasticizers that leave a sticky green film on the note over time and cause permanent damage.
Should I flatten a folded banknote?
No. Pressing does not remove the fold from the paper fibers and it is detectable. A pressed note is graded lower and labeled as such, which reduces value further.