Counterfeit bill checks: pens, lights, and counter habits

How do you check a bill quickly without holding up the line? Counterfeit bill detection at the counter works best as a habit, not a gadget. Pens and UV lights can help, but each has limits. The most reliable check is knowing the security features on real US currency and looking for them on larger bills, every time.

Fake bills show up at every kind of store. Here's how to handle them calmly.

What do counterfeit pens actually tell you?

Counterfeit detection pens contain an ink that reacts with starch in ordinary paper. Real US currency paper is made differently. So a mark from the pen tends to look one way on currency paper and another way on ordinary paper.

That's useful, but limited.

A pen can't detect a counterfeit printed on real currency paper, such as a bleached bill reprinted with a higher value.

Some fakes are made with paper treated to fool pens.

A pen doesn't check any of the actual security features of the bill.

So a pen is a quick first check, not an answer. Don't treat a pen mark as proof either way.

What do UV lights show?

An ultraviolet light, sometimes built into a counter-top detector, makes certain features glow.

Many US bills have a security thread embedded in the paper that glows a specific color under UV light, depending on the denomination.

Ordinary paper often glows brightly under UV, while currency paper generally doesn't.

UV checks catch more than a pen alone, but they still have limits. A skilled counterfeit or a bleached bill may pass some UV checks. Use the light along with a look at the other features.

Which security features should cashiers check?

The US Currency Education Program is the official source for US currency security features. It publishes guides for each denomination and training materials for businesses.

A few features, depending on the bill and design, are worth knowing.

Feel. Real currency has a distinct texture, and raised printing on some parts of the bill.

Tilt. Many newer, larger bills have color-shifting ink in the numeral that changes color when you tilt the bill.

Hold to light. A watermark portrait and an embedded security thread appear when you hold the bill up to light.

Check that the watermark matches the portrait and denomination. A bleached and reprinted bill may show the watermark of a smaller bill.

Train cashiers on these features for the bills you see most often, especially larger denominations. Wikipedia's page on counterfeit money gives historical background.

What habits help at the counter?

Check every large bill, every time. Consistency matters more than speed.

Keep large bills under the drawer tray until the transaction is complete. That also helps prevent quick-change tricks.

Don't let customers rush you. A confident customer pushing to move fast is a signal to slow down.

If you suspect a bill, stay calm and polite. Don't accuse. Follow your store policy, which should include not returning the bill and contacting local police or following the guidance from the US Currency Education Program.

Write down what you remember about the customer and the time.

Taking more card payments reduces the cash you handle overall. If you're setting up card acceptance, learn about NRS Pay. For pens, lights, and counter supplies, browse the store supplies category and the office and school supplies category to see what's available.

Practice helps more than equipment. Once a month, take a real bill of each common denomination and walk new cashiers through the checks: feel the paper, tilt the numeral, hold it to the light, and find the watermark. A cashier who has handled real bills closely is far more likely to notice when something feels off.