Pot of Gold Behavior

My kids have never worked so hard!!!  I showed them my bag of "gold coins" and they are doing whatever I ask them to get the "gold coins" into our "pot of gold."  So far I've got them doing more of their work by saying things like, "If everyone has this work done in 15 minutes, I'll add a gold coin to the pot." 

To make these wonderful "gold coins" all I did was use the ends of fozen lemonade and orange juice containers and spray paint them gold.  They make the perfect "gold."  If you don't use classroom money you could put any reward you wanted to on them.  My kids are filling our pot of gold and at the end of the month each student in my class will receive that much in classroom money.

But you could...

put a reward on them and hand them out to individual students when you catch them being good and they can redeem them later
or
make homework passes out of them and give them out.

Any othere ideas???