Paper is a living material and reacts to humidity, light and the oils on your fingers. The good news: proper storage does not take much money, just a little discipline.
You can own the rarest banknote in the world, but if you keep it in a damp garage or keep pulling it out with bare hands, you will ruin it yourself within a few years. Paper is a living material: it reacts to humidity, light, heat and the oils on your fingers. The good news is that proper storage requires neither much money nor special equipment, just a little discipline.
Sleeves and albums
Every banknote deserves its own transparent pocket. The key is that the material is acid-free and PVC-free, because PVC releases chemicals over the years that turn paper yellow and make it stick to the sleeve, and that can never be repaired. Look for polypropylene or Mylar; they cost a little more, but they do their job for decades.
The same rule applies to the album: not the cheap one from the stationery shop, but a specialised one with acid-free pages. It sounds like nitpicking, but a cheap album is the most expensive saving in this hobby.
Humidity, heat and light
Three quiet enemies. The ideal is somewhere around 45 to 55 percent humidity and room temperature, away from windows and strong light. UV rays slowly fade the colours, and humidity invites mould. If you live by the sea or in a basement flat, a few silica gel sachets in the box work wonders. The worst place for banknotes is usually the first place people put them: a sunny shelf or a damp bathroom drawer.
How to handle them at all
Rule number one: do not touch them with bare fingers unless you must. Sweat and oils stay on the paper even when the eye cannot see them, and over time they turn into stains. Cotton gloves cost pennies. When you examine a banknote, hold it by the edges and never bend it to see a detail better; that is what a magnifying glass is for.
For the more valuable pieces
If your collection grows and something truly valuable finds its way into it, consider professional grading, where the banknote is assessed and sealed in a hard capsule. And keep records: photograph every piece from both sides, note its condition and what you paid. You will be glad of it in a few years when you want to know exactly what you own, and especially if you ever want to insure the collection.