Lemon zest freezes very nicely! I always zest every lemon that I buy, and for that I use the microplane over plastic wrap or a wide, flat bowl. To freeze it, I put it into an icecube tray, one teaspoon of zest per hole, and after it is all frozen I put each little cube of zest into a small plastic sandwich bag, and put the sandwich bags into a larger zipper-style plastic bag. I also freeze lemon juice from any leftover lemons, with the ice cube tray, one tablespoon of juice per hole, and then the plastic bags. Lemons tend to be a bit expensive here, and waste offends me, but the frozen zest and juice take up very little room in the freezer and are so easy to do that I buy extra lemons when they are on a really good sale.