You could always try the "McMahan" approach:
(from Snopes -
https://www.snopes.com/fact-check/legal-tender-payment/)
Senator Chad McMahan
about 10 months ago
Notice to businesses not accepting cash, Legal Tender, in Mississippi.
I've had several people reach out to me about an issue taking place in our state. Scott, thank you for the email.
It is my understanding several companies in Mississippi are refusing to take cash as payment.
Take a look at the photos attached. This is a Federal Reserve Note, a $20 bill. This paper money, this note, is Legal Tender for all debts, public and private.
Business owners, if you refused to take cash, the debt is paid in full. If you are a business owner and you refuse to take cash, you are breaking the law.
Here is an example, if I stop by your store and I purchase $44 worth of fuel, and I try to pay you with a $100 bill and you refuse payment of cash, the debt is paid in full. There is nothing you can do to prosecute me because you have refused payment of Legal Tender, unless the business suspects counterfeit bills.
I'm asking residents of Mississippi to make me aware of companies who will not receive or take your cash. They will be receiving a call from my office, the Department of Revenue, and the Attorney General's office.
SEPARATE ISSUE
We are experiencing a coin shortage. Due to this event, some companies are requesting correct change. That is understandable and you should be able to work out any change issue since we are talking about less than .99 cents on any transaction.
My office #601 359 2886.
Spoiler Alert: It didn't work for him either ...