My parents travelled throughout Europe, and either sentimentality or absent-mindedness had them hanging onto a large jar of pre-Euro Deutsche Marks, Kroner, Schillings, and Irish coins - not pfennigs and farthings, but real money, had they redeemed it before the deadlines.
Some of the coins are old-ish, some of the English still say 'new money' from their transition to decimals, and the Irish and French coins are fairly dramatic.
Is there a reliable guide to see whether any of these have collector value?