EWTN Catholic Q&A
Question from Sr. mary Terence on 04-13-2005:

Is it true that some coins are put in the casket with the Pope,What is the purpose of this action? Thank you

Answer by Matthew Bunson on 04-14-2005:

Yes, a set of coins is placed in the inner coffin (the cypress one) representing each year of issue of Vatican coins of the pontificate. The coins are one way of commemorating the reign. Normally, they are placed in a red velvet pouch before being included among the effects in the coffin.