 Contemporary practice is to set aside "terumah", separate first tithe ("ma'aser rishon"), separate "terumat ma'aser", separate either the second tithe or the poor tithe (depending on the year), then (if applicable) redeem the second tithe with a coin.The coin can be a minimal amount capable of purchasing food and need not be the value of the produce.When the value of the coin is "filled", the coin can be redeemed on a coin of higher value or discarded in a way that prevents its future use.