Taxes (at least US federal) are one of the few things you can pay for in unlimited amounts with cash.

They have a nice page about how to make an appointment (recommended 30-60 days in advance): https://www.irs.gov/payments/what-to-expect-when-you-pay-cas...

Fun fact: One of the most closely guarded pieces of paper in those offices are the tax receipt forms. Because if you can produce a tax receipt it's good as cash for meeting your tax obligations.

"Hi, IRS? I've got a billion dollars worth of 'other, unspecified' income I need to pay taxes on in Cash. My name? Uh...."

If the person on the phone had said “Capone, Al” instead of “Uh…” he’d possibly not gone to jail.

Even ill gotten gains are taxable and the theory of one crime at a time suggests that even “other, unspecified” could be with paying taxes on to reduce the likelyhood of successful criminal persecution.

They’d have nailed him with something else - it just might not have been so easy.

That said, pay your taxes even if you’re a criminal for sure!