Take all the keys off and vacuum the loose stuff out. They should pop off fairly easily. You may need to use a small screwdriver to get the first few off but you should be able to pry them off with your fingers. Use a damp paper towel or something to get the food off the actual keys. It may take a bit more time but you'll be able to use it immediatley after you put it back together. The keyboard I'm using this second is 8 years old and still going strong thanks to a little regular maintainence.
all ive ever done is pop a few keys off, and get some compressed air to blow the **** out from under the keys or blow to one of the empty spots where you took off a key.
I got my roomate's spacebar back on when he took it off
The compaq keyboards are ****ing insane I took the spacebar off then tried for 20 minutes to get the thing back on so i went and bought a new keyboard.