How to Identify Counterfeit Banknotes in Colombia and Avoid Fraud When Receiving Cash in Sales

Selling second-hand items in person remains one of the fastest ways to get liquidity in Colombia. Whether you are handing over a cell phone, a laptop, a set of furniture, or a motorcycle, cash-on-delivery is usually the preferred method to avoid banking delays. According to active listings on Colombia Move (September 2026), there are 11 cell phone ads, 9 computer ads, and 6 motorcycle ads—exactly the categories where cash-on-delivery is most common. However, closing a face-to-face deal with strangers carries a silent risk: receiving counterfeit or adulterated paper money.

Scammers know that during an in-person delivery, the seller is focused on the conversation, the condition of the product, and their surroundings, which creates the ideal moment to introduce fraudulent banknotes in high denominations like $50,000 or $100,000 pesos. If you know exactly what to look for before handing over the item, you can verify any stack in a matter of seconds without creating awkward moments.

The official method from the Banco de la República: five infallible steps

The Banco de la República de Colombia (BanRep) designs the current series of banknotes with multi-layer security technology. To verify the authenticity of any bill on the street or at your home, the entity recommends applying the five-action rule: Look, Touch, Lift, Tilt, and Check.

In quick second-hand transactions, you do not always have an ultraviolet lamp or a magnifying glass. Therefore, the fastest and most effective filter for any seller is to combine Touch + Tilt: the relief texture of the cotton fiber and the dynamic color change in the central figure are almost impossible to replicate with quality in clandestine printing shops.

How to check $100,000, $50,000, and $20,000 bills in seconds

High-denomination bills are the most common targets for counterfeiting rings due to the profit margin they obtain from each fraudulent transaction. Knowing the distinctive features of each will allow you to validate them instantly:

$100,000 bill (predominantly green)

Dedicated to President Carlos Lleras Restrepo and the Cocora Valley with the wax palm. When receiving it, focus on two key elements:

• Sietecueros flower (when tilting): Located on the obverse to the left of the character. When tilting the bill in front of your eyes, the color changes cleanly from green to intense blue, while an internal circle shifts with the movement.
• Security thread: When moving the bill, the integrated security strip changes from fuchsia to a greenish-yellow hue.
• High relief: Run your fingertips over the text "100 MIL PESOS" and over the suit of Dr. Lleras Restrepo; you will notice a rough and unmistakable relief.

$50,000 bill (predominantly violet)

Pays homage to Nobel laureate Gabriel García Márquez and the Lost City (Ciudad Perdida). It is one of the denominations with the highest circulation volume in local commerce:

• Hummingbird pecking a flower (when tilting): When moving and tilting the piece, the bird changes from green to blue, revealing a bright green circle that appears to float inside it.
• Watermark and burgao snail: When lifting the bill against natural light, Gabo's face is visualized with soft three-dimensional shadows, accompanied by the figure of the burgao snail that fits perfectly with the print on the reverse.
• Relief text: The words "BANCO DE LA REPÚBLICA" and the silhouette of the standing Nobel laureate have a pronounced texture.

$20,000 bill (predominantly orange)

Homage to President Alfonso López Michelsen and the pre-Hispanic channels of La Mojana:

• Annona fruit (when tilting): The fruit stamped on the obverse changes from green to blue when moving the surface.
• Vueltiao hat: When lifting the bill, the texture and graphic details of the typical hat are complemented against the light with millimeter definition.

The 4 most common deception methods in classifieds deliveries

Identifying fake bills is not limited to looking at the paper; it also implies anticipating the behavior of malicious buyers. According to recurring security reports in private trade, these are the most repeated tactics:

• The sandwich bill: The buyer hands you a stack of money where the outer bills (the first and the last) are authentic, but the inside is composed of crude copies or smaller denomination bills folded strategically. Golden rule: count and feel each bill one by one, regardless of any apparent rush.
• Induced hurry and distraction: They arrive in a running vehicle, constantly looking at their watch, talking loudly on the phone, or asking you to pack quickly because they are poorly parked. The intentional haste aims to make you put the money in your pocket without verifying it.
• The immediate switch: Occurs when the scammer pretends to regret the purchase after handing you the money, asks for the cash back to check it, and then, in a quick sleight of hand, gives you back fake bills while canceling the operation or insisting on negotiating a discount.
• Mixed payment with an adulterated receipt: They show you a fake screenshot of a financial app claiming that they only missed transferring a part, and they complete the remaining balance with suspicious stacks of cash so that the confusion prevents verifying both amounts with rigor. If you post on open platforms, check where to sell used things in Colombia with good practices to protect your deals.

Do fake bill detector markers work?

Many merchants resort to iodine-based pens or chemical markers that mark amber on authentic banknotes and black or purple on regular paper. Although they can serve as a superficial first filter for prints on bond office paper, they are not an infallible method.

Criminal organizations often use bleached paper or chemically "washed" low-denomination genuine banknotes to print $50,000 or $100,000 values over them. In these cases, the marker will incorrectly detect genuine cotton fiber. The definitive test will always be to verify the tactile relief, the watermark when held up to the light, and the color change when rotating the piece.

Security protocol for closing cash sales without setbacks

If you are going to close an in-person sale for a significant value, follow these preventive steps to take care of both your finances and your personal integrity:

1. Choose a monitored meeting point: Avoid lonely alleys, desolate bus stops, or nighttime appointments. Finalize the delivery in a shopping center food court with security cameras or in the vicinity of a National Police CAI.
2. For sums over one million pesos, use a teller or ATM: Agree to meet directly inside a bank branch. Ask the buyer to deposit the money into an automatic multifunctional ATM into your account before handing over the product. The ATM electronically validates the authenticity of each banknote before crediting it.
3. Verify first, deliver later: Keep the product in your possession while you count and carefully check each banknote. Do not release the item until you are fully certain of the total payment.
4. Stay calm if you encounter a dubious banknote: If you detect a suspicious piece, do not engage in violent confrontations. With a neutral and firm tone, say: "This banknote does not pass the security test; please change it for another or we can perform the transfer via a verified digital channel". If the person becomes aggressive or evasive, cancel the deal immediately and retreat to a safe zone.

Frequently Asked Questions

❓ What is the fastest way to know if a 50 thousand or 100 thousand peso banknote is fake?

Feel the relief and turn the banknote: the hummingbird or the flower must change from green to blue. Do it in less than five seconds, in full light, before handing over the item.

❓ Is the chemical marker useful for detecting fake banknotes in Colombia?

The chemical marker detects common cellulose paper but may fail with washed or adulterated genuine banknotes; therefore, it should always be complemented by the tactile and visual inspection from the Banco de la República.

❓ What should I do if a buyer hands me a fake banknote during a sale?

Refuse the banknote calmly by requesting another means of payment or an authentic banknote, and if you perceive evasive or intimidating attitudes, stop the delivery immediately without exposing yourself to physical confrontations.

❓ Can I go to a bank to exchange a fake banknote that I received by mistake?

No, banking entities in Colombia retain and seize fake banknotes under an official act without refunding their value, sending them to the Banco de la República for final destruction.

❓ Is it a crime to pay with a fake banknote again if I was a victim of deception?

Yes: knowingly recirculating a fake banknote is a crime in Colombia. According to the Penal Code (Law 599 of 2000, article 274), hand it over to a bank or destroy it; do not use it to recover your loss.

❓ Where is it safer to collect cash for large sales in cities like Bogotá or Medellín?

The safest place is inside monitored shopping centers or directly at a bank's ATM area to immediately deposit the cash before handing over the item.