Sealing your four and five leaf clovers in plastic is one of the best ways for it to retain its color for a long period of time. It also vastly improves the durability of the clover itself. Once cut out the clovers can be placed in your wallet, framed, in a phone case, or wherever you can think to put them.
The only real challenge is trying to find a four leaf clover. Good luck, and happy hunting!