I try not to. My brand new MacBook Air is actually owned by the school where I work, and I can't afford to replace it if I trash it! I don't like the keyboard membranes as I type rather quickly; the membrane slows me down and letters get all jammed together and such, so membranes don't work for me. I just try to remember to use a plate if I must eat while using the computer- and no liquids (which is not fun on Sunday morning, when I want to have my coffee and surf the net!)