Can I destroy US currency?

Question

From what I understand, destroying US currency is illegal with 0 exceptions. Legal Information Institute says: “Whoever mutilates... cements together, or does any other thing to any bank bill... or other evidence of debt issued by any national banking association... with intent to render such bank bill... or other evidence of debt unfit to be reissued, shall be fined not more than $100 or imprisoned not more than six months, or both.”

This means that no US currency can be destroyed right? Except we did a chemistry lab on campus where we dissolved US pennies from around the 1960’s I believe. Since we “rendered it unfit to be reissued” then why wasn’t there any consequences? Did we do this illegally? They have been doing this for quite some time, how has there been no problems? My chemistry teacher actually tried to claim that people can burn US currency as long as you don’t go try to exchange it and use it as if it were legal tender. He said you can go exchange partially burned money at the bank, just don’t exchange it somewhere else like a store because “That’s were it becomes illegal”. This is in Minnesota, United States of America

Please make sense of this for me, or interpret the law in a different way if I’m wrong, thanks!

Link to law: https://www.law.cornell.edu/uscode/text/18/333

Answer 1

Yes, and no

You can't legally destroy banknotes but you can destroy coins. You can't "fraudulently" alter coins but that's not what you were doing; you were doing a science experiment, not committing fraud.

The law prohibits the destruction of "bank bill, draft, note, or other evidence of debt": a coin is none of those things. The first three are obvious, and evidence of debt is a written obligation such as "a promissory note, bond, negotiable instrument, a loan, credit, or similar agreement, or a monetary judgment entered by a court of competent jurisdiction"; not a coin.

It's a bit of a historical anachronism because when these legal distinctions were made, coins had intrinsic value; they were actually made of gold or silver or some other precious metal. They were not tokens of value like banknotes and all the rest are; they were physical repositories of value. Of course, in many countries today, coins at the lower end of the scale actually contain more value in their metal than the face value of the coin while those at the upper end contain much less.

Answer 2

TL;DNR: It is currently illegal to melt down pennies and nickels in the US.

US law (31 USC § 5111(d)(1)) gives the Secretary of the Treasury the power to "prohibit or limit...the melting of US coins when...necessary to protect the coinage of the US." In 2007, the Secretary (ie, the US Mint) used this power to issue a rule (31 CFR § 82.1(a) & (b)) making it illegal to "export, melt or treat" pennies or nickels.

The rule was adopted after rising zinc and copper prices meant the metal in pennies and nickels was worth more than the face value. In response, people were melting down coins, or sending them abroad to be melted. Since the Treasury lost money on every penny or nickel it minted, it wanted the melting of them stopped.

A broader lesson?

In itself, this is just footnote to Dale's answer. But there is a bigger point, especially for LSE users. In the modern regulatory-state, law is more than statutes. This means that finding statutes is often only the first step in determining exactly how law constrains us.

Tracing through this web of statutes, rules and judicial decisions to find the exact constraints imposed by law is not always easy. The history of this question is a case in point. Dale & I both looked at this question when it was posted. We found only the statutes he cites. (Since he got there first, there was no need for me to write a duplicate answer.) Yet it turns out neither of us found this statute, or the resulting rule. Nor is it clear how we would have found it. I am not an expert in this part of money & banking law, so I didn't know what I didn't know. It wasn't until I saw hszmv's comment that I looked again, and found the rule, which led me to the statute.