I am doing a "Penny Persuit" for my school. Help before Fri. the 15th (2010)?

Ok so you put pennies in a jar and whoever at the end of next week (1-15-10) has the most pennies wins the amazing prize of a pizza party, dessert and a movie!!!. Ultimately this is a fundraser for our school. But there is a catch. You can "sabatoge" people by putting silver coins into their penny jar. This subtracts the amount of pennies they have (raising MORE money for the school) but lowering our chances of winning.

Heres our strategy so far. We keep our coins secretly in a jar in our classroom. We keep a penny jar and a silver jar. On thursday I will take all the silver coins to a bank and turn them into pennies. Same with dollar bills. Ill collect them and turn them to pennies. Then on Friday, no one has sabataged us because it looks like we dont have any pennies in our jar. At the last minute, we dump all of our pennies into the jar and VWALA.

Pretty good right? No? HELP ME!

If you have a better strategy or a tip for me PLEASE PLEASE PLEASE dont hesitate to answer!

Thank you ahead of time,

MONKEY! :)