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Aeris™ Banknote
Cleaning Technology
Technical Press
and Articles
Evaluation Program
for Central Banks

Worldwide, nearly 150 billion new banknotes are printed annually to replace those that have been deemed unfit due to soiling and wear. Considering the costs associated with removal and destruction of unfit currency and the manufacture of new banknotes, governments spend nearly $10 billion annually to maintain circulated currency at acceptable levels of fitness.

In an attempt to reduce the costs of banknote replacement, the industry has focused on the development of solutions to extend banknote life with new substrate materials and printing techniques. Recognizing the primary cause of banknote degradation, which involves the buildup of sebumBanknote Cleaning (oily substance produced on human skin) that attracts soil and degrades the paper substrate, Spectra Systems developed a banknote cleaning solution that lifts sebum and other substances from the banknote using a dry process based on supercritical CO2 cleaning.

Because CO2 in a supercritical state has the density of a fluid but behaves like a gas, the CO2 can easily pass through stacked banknotes allowing for high volume cleaning and easy handling by staff during the cleaning process.

Banknote CleaningUnlike traditional cleaning fluids that can damage the material they clean due to their harsh chemical properties, supercritical CO2 dissolves waxy and oily substances. The Aeris™ process extracts those substances from the cleaning chamber leaving the banknotes clean and dry without damaging the paper substrate, inks and costly security features. Ongoing in-house and central bank tests with our Aeris™ machine, which can clean up to 500,000 notes per eight hour shift, could potentially save a significant percentage of notes which would otherwise be destroyed or replaced.

Banknote CleaningExtremely soiled banknotes destined for destruction can be cleaned in bulk form prior to machine or manual processing in a way that protects staff from built-up contaminates (heavy metals, bacteria, viruses, and pesticides). Typically, currency received in this condition poses health risks to the processing staff. Cleaning such extremely soiled and contaminated notes enables safe handling and increased ability to determine the authenticity of these notes.