Nobody will accept a €500 note in Europe - not even banks - you have to get it changed at a central bank, and you can expect a lot of questions, like “what kind of drugs did you sell to get this?”

An easier option if you have one, is going to a forex office in Vietnam or somewhere - and even then they may not take it.

I was lumbered with a couple of them for a few years, until I dumped them in Uruguay.

That's weird. Can't think of a legal basis that would allow the bank to refuse it. They have machines that verify it's not counterfeit after all. People regularly pay for used cars with cash here, and I've never heard of anyone refusing a 500€ note.

Yeah, it's truly strange because up until around 2012, I used to pay my rent with €500 notes when I lived in Spain. Just go down to the bank and get them. Then there was some sort of crackdown on drug smuggling and no one would touch them. Barbaric, rather fascistic or communist way of dealing with a social problem, since of course this means normal people can't pay rent in cash anymore without a ton of bills, and the only real purpose is to track so much more of the casual, unofficial economy. Drug dealers do find ways around.