What To Do With Foreign Coins

It comes from the notion that a collector knows more about the dark side of the moon than they do about whatever it is you are calling dark side or darkside.

For what it is worth, I learned that from Sap. Until then, I always thought it was like the dark side of the force. "Those coins are evil. EVIL!"

"Darkside" is Internet coin forum slang. The term was invented over a decade ago, either on the PCGS forum or a now-extinct forum; it was originally applied by American collectors of American coins, to American collectors of World coins. As jbuck said, it derives from the notion that your typical American coin collector knows more about the dark side of the moon than they know about foreign coins. In a North American context, Canadian coins are considered "greyside" - not quite as dark.

As for the OP's question: if you're sure you have no interest yourself in them and don't want to keep them, then selling or trading them away is probably your best option. If you're feeling generous or having trouble finding anyone to take them, you could always give them away; some charities have big moneyboxes at airports where travellers returning from overseas can dump unwanted foreign coins. Other charities no doubt also have means of disposing for profit of any coins donated to them.