We got the idea off this board before our second trip, so I thought I would share it for newer folks. We found a glass jug that had cider in it, it was the perfect size. We made our own cover for it labeled it "Our Jamaica Jug". All of our silver change goes into this jug throughout the year.
We cash it in before our trip to couples and it is used for any excursions, or extra's such as massages or if you dream of that private dinner on the beach, here is a way of saving for it separately without feeling it.
We also start saving 1 and 5 dollar bills a month or two before the trip to use for tips outside the resort/airport/massages etc.