Counterfeit pens are actually really inaccurate and a lot of places don't use them anymore.

Counterfeit pens are actually really inaccurate and a lot of places don't use them anymore. In fact, I believe there is a case of like a child using an older bill at school and they got arrested because it was so old that the chemical composition it didn't have the starch in it that the counterfeit pens react to. And that causes it to turn clear. However, what a lot of people will do criminals is they'll bleach a lower denomination like a $5 bill or a $1 bill and then they'll print a higher denomination like a 20 or 50 or 100 on top of it. So if you check with a pen, it's still real money. It still has the starch in it. So it's still going to show as a real bill. Also, you can get a $50 or $100 bill, any bill, it could go through the wash, have something spilled on it like vitamin C, some kind of detergent, something could change the chemical composition of it or like create like a layer of it, would cause it to show as a fake bill when it's really real. So the marker is just really an inaccurate way. If you're handling currency on a daily basis as your job, I recommend looking into, which I can make a video on this as well, how to tell if a bill is fake from other ways because there's a million other ways to tell and it's a lot easier than the marker, I think.