My grandfather used to say, “Don't take wooden coins.”
The idiom basically meant, “Be careful! Don't be fooled.”
In the past, small banks and merchants sometimes gave out wooden five-cent coins as promotional items. Of course, they had no value. You didn't want to be tricked into accepting a wooden five-cent coin instead of real money.
Today, you could say with equal accuracy, “Don't accept a penny.”
President Donald Trump recently announced the demise of the penny and ordered the US Mint to stop producing the 1-cent coin because of its cost. According to the Mint, it costs 3.69 cents to mint and distribute a penny.
But there is still a problem: the nickel.
The nickel problem
By phasing out the penny, the Mint will have to produce more 5-cent coins. The problem is that they cost more to manufacture than a penny.
In fact, a “pro-penny” group called Americans for Common Cents argues that eliminating the penny will cost the government more than continuing to produce it.
"Without the penny, the volume of five-cent coins in circulation would have to increase to fill the gap in small-value transactions. Far from saving money, eliminating the penny shifts and amplifies the financial burden.”
(Full disclosure: According to CNN, Americans for Common Cents is primarily funded by Artazn, the company that has the contract to supply the banks used to mint pennies).