Some German banks (e.g., Commerzbank) have an "Einzahlungsautomat", basically a reverse ATM that accepts deposits as bills or coins. Collect the coins in a jar

Some German banks (e.g., Commerzbank) have an "Einzahlungsautomat", basically a reverse ATM that accepts deposits as bills or coins. Collect the coins in a jar and once a year hit the ATM.