My uncle used to save 5 cent guilder coins (stuivers in Dutch). I don't know why, maybe he wanted to be a copper Scrooge McDuck it was an obsession of his, always ask people if he could change some money with him. After a while he had many of those plastic drum barrels full of coins in the attic. The problem was that the ceiling under the attic started to visibly bulge, so they decided to bring them to the bank. He said that all the work was worth it to see the expression on the bank tellers face when they rolled those barrels in the bank.

Only if they know the rule tho

Iirc only banks can't refuse.

Well they're not obliged to do business with you at all.

That kind of thing is sometimes not allowed even here in the US, precisely because it's a form of malicious compliance.