Collector's Guide · Care and Storage · Updated September 2026

How to Store Banknotes: Sleeves, Holders, and the Five Things That Ruin Paper Money

A banknote that survived a hyperinflation, a war, or a century in a drawer can be undone by a rubber band and a sunny windowsill. Here is how to store paper money so it is in the same condition in thirty years as it is today, what to buy, what to throw away, and the one mistake we see more than any other.

What is the best way to store banknotes?

Paper money is paper: cotton and linen fibers, printing ink, and on modern notes a layer of security features that includes foils, threads, and optically variable inks. Everything that damages paper damages banknotes. The goal of storage is to keep four things away from the note: acid, plasticizers, moisture, and light. The cheapest way to do that is a good sleeve inside a closed container, and it costs less than a dollar a note.

"Inert" means the plastic contains no plasticizers and releases no acids or gases over time. Polyester, polypropylene, and polyethylene qualify. Soft, flexible PVC does not.

Why should you never store banknotes in PVC sleeves?

Soft polyvinyl chloride, the flexible plastic that smells faintly of a new shower curtain, stays flexible because of plasticizers mixed into it. Over years those plasticizers migrate out of the plastic and into whatever it is touching. On a banknote that means a greasy film, then ink that lifts or transfers to the sleeve, then a note that is permanently stuck to its holder. The damage is slow, invisible for the first few years, and irreversible.

The tell is the feel. If a sleeve is limp, cloudy, and rubbery, it is soft PVC and it should not touch a note you care about. Polyester and polypropylene sleeves are crisp, clear, and slightly stiff. When a supplier says "archival," "acid-free," or "PVC-free," that is what they mean. Rigid holders are a different case: hard, unplasticized plastics are stable, which is why grading services and quality holder makers use them.

The most expensive storage mistake is the cheapest sleeve. It takes ten years to find out.

What are the five things that ruin banknotes?

1. Light. Ultraviolet light fades ink and yellows paper. A note framed on a sunlit wall will be visibly faded within a few years, and the fading cannot be reversed. Display away from windows, use UV-filtering glass if you frame anything, and keep the rest of the collection in a closed box or drawer.

2. Humidity. Damp air feeds mold and foxing, the brown spots that bloom on old paper. Dry air makes paper brittle. Aim for 35 to 55 percent relative humidity and a temperature that does not swing. A closet in a living space is fine. A garage, attic, basement, or safe-deposit box in an unconditioned vault is not. If you use a safe at home, put a silica gel packet inside and replace it when it saturates.

3. Folding and bending. One fold turns an uncirculated note into an About Uncirculated note and can cut its value by half. Notes should never be folded to fit a sleeve, a wallet, or an envelope. Ship them flat between rigid card stock.

4. Fasteners and adhesives. Rubber bands leave a permanent stripe as they decay. Paper clips and staples rust and leave holes. Tape of any kind leaves adhesive that migrates into the fibers. Post-it notes count as tape. None of this is repairable.

5. Hands. Skin oil transfers to paper on contact and shows up as a dull fingerprint years later. Handle notes by the edges, with clean, dry hands. Cotton gloves are common in museum settings but reduce your grip, and a dropped note does more damage than a careful bare hand; the better habit is washed hands and edge-only handling.

How do you store oversized banknotes like the Zimbabwe 100 trillion?

This is the mistake we see most. Standard currency holders and sleeves are sized for modern U.S. notes, roughly 156 by 66 millimeters. The Zimbabwe trillion series, Venezuela's Bolívar notes, many older European large-format notes, and most of the notes collectors call "horse blankets" are taller than that. The Zimbabwe 100 trillion is 74 millimeters tall. In a standard holder, the top 8 millimeters of the note sit exposed above the edge, which is exactly where corners get bent and edges collect dirt.

Measure the note before you buy the holder. Large-format sleeves are sold in several sizes, and rigid holders cut specifically for the Zimbabwe trillion series exist because the problem is so common. Our sister company PBGrade makes a rigid holder at 79.4 millimeters tall for exactly this reason: the whole note is enclosed, with no edge exposed. The same rule applies in reverse; a small note rattling around in a large holder slides against the plastic and picks up scuffs.

Should you clean, wash, or press a banknote?

No. Not ever, no matter how tempting a light crease or a small smudge makes it. Washing removes the sizing that gives paper its snap and leaves it limp and slightly fuzzy. Pressing flattens the embossing that original printing leaves in the paper. Both are detected immediately by PMG and PCGS graders, who withhold the EPQ or PPQ paper-quality designation, and by any experienced dealer, who will discount the note as "processed." A note with an honest fold is worth more than the same note with the fold ironed out. Our PMG grading guide explains what the paper-quality designations mean and why the market prices them.

How should you store bank packs and consecutive bundles?

A pack of 100 consecutive notes is one object, and its value depends on staying that way. Leave the original bank strap on; it is part of the provenance. Store the pack flat in a rigid box sized to it, never on edge, never with anything on top of it. Do not remove notes to examine them and put them back; the ones on the outside of the pack take all the handling wear, and a pack that has been picked through shows it. If you need to sell singles, break the pack deliberately and sell the rest as a partial run. Our post on bank packs and bricks covers what makes them collectible in the first place.

Frequently asked questions

What is the best sleeve material for banknotes?

Polyester, sold under the Mylar and Melinex brand names, is the archival standard and the stiffest. Polypropylene is nearly as good and cheaper. Both are inert. Avoid anything soft and flexible, which is almost always plasticized PVC.

Can I store banknotes in a safe?

Yes, with two conditions: the notes are sleeved, and the safe has a desiccant inside. Sealed safes trap humidity, and fire-rated safes in particular can hold moisture in their insulation. Check the silica gel every few months.

Is it safe to frame a banknote?

If the note is in an inert sleeve, the mat and backing are acid-free, the glass filters UV, and the frame hangs out of direct sun, yes. Skip any one of those and the note will fade or yellow. Never mount a note with adhesive.

Should I take a graded note out of its holder?

No. The sealed holder is the certification. Once it is opened, the grade no longer applies and the note has to be resubmitted. Store graded holders on edge in a slab box, out of light.

What humidity should banknotes be stored at?

Between 35 and 55 percent relative humidity, at a stable temperature around normal room conditions. Stability matters more than the exact number; repeated swings do more harm than a steady 60 percent.

Do polymer banknotes need different storage?

Less, not different. Polymer notes resist moisture and handling far better than paper, but they still fade under UV, they crease permanently if folded, and heat can warp them. Sleeve them the same way and keep them out of hot cars.

What size holder does a Zimbabwe 100 trillion need?

The note is 148 by 74 millimeters. A standard 66-millimeter currency holder leaves the top 8 millimeters exposed. Use a large-format sleeve or a rigid holder cut to at least 75 millimeters in height.

Sources

• Library of Congress Preservation Directorate, guidance on storage of paper-based collections
• PMG and PCGS Banknote, holder specifications and paper-quality designation standards
• International Bank Note Society, grading standards (definition of original paper)
• Planet Banknote and PBGrade, 15+ years of handling, shipping, and housing world banknotes