What is the best way to check for counterfeit money when making a sale?

Level 4

I will try this again. My first post disappeared. lol

I recently lost a lot of money from a person handing me fake 50s.

I know next I will go to a police station lobby where there are videos if I have a higer priced item to sell.

What is the best way to check for funny money? The bank teller told said the PEN isn't 100 accurate.

Is using that 'light' the best way to go? Any recommendations of which light to purchase? I want the most accurate.

I was also considering putting a disclaimer in my higer prices listings to let buyers know that I will be checking for fraudulent bills.

 Thanks for any suggestions.


Always protect yourself and don't trust anyone!!!! Check the money.


Buyers have opened my brand new boxes to make sure I didn't put bricks inside so don't feel bad to have to check the money. My incident and loss was a big wake-up call and lessons learned.

Community Helper
@Diddlydoo let me be one of the first to welcome you to the OfferUp Community forum,

Diddlydoo UV Light - Counterfeit Bill Detectors 365 nanometers “Loungwave “ is best for examining currency. For example try to avoid 395 nanometers lights this one doesn’t pickup the security threat in the currency because it’s the wrong wave length. Also remember UV lighting can be overwhelmed by room lighting or sum lighting. I’ve personally found the best things to have with in any money transaction, is a "Money Authentication Pen" Worth about $10 purchase at most business supply stores.
please remember to report any users that do not adhere to OfferUps TOS & Guideslines. 😎🇬🇧🔚

OfferUp Customer care
Level 9
I'm sorry that happened to you - that's so infuriating!
This probably isn't the BEST way to check for fake money, but I've found that being familiar with the security features of each bill (watermark, metallic paint, security strips, holograms etc) is a great place to start.
I had someone (not from OfferUp) hand me a $50 that looked fine, but when I held it up to the sun there was a big 5 watermark where Grant's face should have been.
Once I saw that, I picked up the other mistakes: the metallic paint on the 50 was flat instead of shiny, and there was no security strip running along the face of the bill.
Someone had washed a $5 dollar bill and run it through a printer.
Level 1
This works....
From the side of the bill tear halfway if it stops almost in the middle it's real.