After Limestone County made one of its largest counterfeit cash busts this past week, some residents are searching for the best way to recognize counterfeit money.

A Limestone County sheriff’s official said $23,000 of the $27,400 in cash confiscated during last week’s bust was fake. The funny money, which came in $100 denominations, was of passable quality but not the best law enforcement officers had ever seen.

Deputy Stephen Young said one of the best ways to tell whether a bill is fake is by touch. Real money is made of 25 percent linen and 75 percent cotton and has small, randomly disbursed red and blue security fibers embedded throughout the paper, according to the United States Secret Service website at https://www.secretservice.gov/data/KnowYourMoney.pdf.

“That’s why you can wash it in the washer, and it comes out OK,” Young said. “Fake money doesn’t do so well.”

Real money also has a slight texture to it, whereas fake money is usually made on a photocopier and tends to be very slick.

Imperfect borders

Young listed a few other ways residents could discern real from fake money.

Real money has a perfect border at its edge while fake money, like that seized last week, often has an uneven border because the bill is not uniformly cut, Young said.

He also noted the images on the fake $100s confiscated last week — particularly the images of Independence Hall on the backs — were a little muddy, or not as crystal clear as they are on real bills.

Go to the light

One easy way to check to see if you received fake cash is to hold it up to the light, Young said. Light will show off the watermark and the security thread in the bill, neither of which will be found on most fakes.

Visible from either side of most bills when held up to light is either a rough sketch of the president on the front (except for the $10 bill, which features Alexander Hamilton) or a large numeral reflecting the bill’s denomination, as with the $5 bill. On some bills, this watermark can be found inside a lighter field of off-white on the bill. You won’t find a watermark in the fake cash that sometimes floats around Limestone County.

While you are holding a $100 bill or most other notes, also check for a thin thread embedded vertically across the bill. It looks like someone typed a tiny, sideways message that stretches from the bottom border to the top border of the note, including into the margin.

What that type actually lists is the denomination of the note. If your eyesight is fading, the thread may look like a faint gray stripe running from the top to the bottom of the bill. Each denomination has a unique thread position and glows a different color when held to ultraviolet (UV) light. The thread is not present in $1 and $2 bills.

More tips

Young urged residents to go online to the Secret Service’s website to learn a few more security measures used in the $100, $50, $20, $10 and $5 bills. Among them are:

• Color-shifting ink — The newer federal reserve notes in $10, $20 and $50 denominations have color-shifting ink that shifts from copper to green as the note is tilted 45 degrees. The $100 note has a color-shifting “bell in the inkwell.” The $5 note does not have color-shifting ink; and

• 3-D security ribbon — The 2004-style $100 notes features a blue ribbon woven into the paper. When you tilt the note forward and backward, the bells and “100s” move side to side. If you tilt the note side to side, they move up and down.