I am still amazed at how many retailers get stuck with counterfeit bills. You wouldn’t allow someone to come into your store and take something in exchange for an IOU; why would you allow them to give you a piece of paper that may or may not be real currency? If you don’t have a counterfeit detecting pen, get one here, if you do have them use them. Just in case you aren’t convinced here is an article from redding.com:

Counterfeit money circulating through Shasta and Trinity counties
cost residents and store owners several hundred dollars in April.

“We have been getting some counterfeit bills — $20s, $10s, $100s,”
said Rob Wilson of the Redding Police Department’s financial crimes
unit. “It’s been sporadic, and we can’t pinpoint specifics. We don’t
know if they’re related or not. A few of them have been obvious, and
some of them have been really good.”

Hayfork was particularly hit hard by the counterfeit money as
nearly every establishment reportedly received fake $20s. Most Hayfork
businesses learned of the fraudulent currency coming through town and
started using counterfeit identification pens to check all bills. This
allowed at least three store clerks to identify false $100s, $10s and
even $1s at checkout counters.

Store owners were instructed by the bank and local sheriff’s
deputies to keep the counterfeit cash at the expense of the customers
and to record the patron’s contact information.

“If somebody comes in to pay with a large bill, and they’re only
paying for a few items, (clerks) should really check that bill — its
security strip; check it with a pen,” Wilson said.

Jerry Reichelderfer, pharmacist and owner of the Hayfork Drugstore,
said the store sold out of counterfeit marking pens within a day or two
of the counterfeits surfacing in town. Counterfeit detection pens are
available at most office supply stores, but the pens don’t work on some
of the false bills.

At Wiley’s Market in Hayfork, one of the bills marked with a pen
showed the desired yellow ink on the front side of the bill, but the
ink on the other side turned brown. That’s when the cashier suspected
the $20 bill to be a fake and noticed it had no watermarks.

North Valley Bank, the only bank in Hayfork, referred patrons to a government Web site, www.secretservice.gov/money_receive.shtml, that gives specific instructions regarding how to identify imitation money and what to do with it.

The site instructs clerks not to return counterfeit money to the
passer. It further asks people to delay the passer if possible, observe
his or her description, and take down the vehicle license plate number.

Store employees in Hayfork said it was awkward for them to follow
these mandates because they know most of the people who carried the
counterfeits and thought they unknowingly possessed the fake money.

Storeowners agreed that their patrons seemed surprised and upset
when their bills were identified as counterfeits. At least two of the
people who had counterfeits reportedly said they got them in change
from bars, places less likely to check for fake bills.

Letha Anderson, a cashier at Frontier Fuel Mini Mart, identified fake money from two customers.

“The first one was trying to buy a can of chew with a $20. He
handed me the money, and I checked it with a pen like I always do, even
though I know him because he’s in here all the time,” he said. “I told
him, Hey this (isn’t) real.’ He asked if he could have it back, and I
told him: No way!’ ”

Storeowners in Hayfork said no one has come by to collect the bills
or even record serial numbers or other markers that might help law
enforcement find out where the bills originated.

The Trinity County district attorney’s office said they were made aware of the counterfeits on Friday.