You can disassemble it very easily, and vacuum it in about 20 minutes.
After this dust, your keyboard become white again and the keystrock easier.
This Instructables is also possible with other keyboards.
Step 1: Disassembling of the Keys
Step 2: Sort the Keys
Step 3: Vacuum the Keyboard
You can also sweep the keyboard with a wipe (I used a wet baby wipe) in the denuded keyboard.
Step 4: Reassembling
Take a key and replace it : put it in the right place and press it highly.
In the big keys, there are an small iron wire : be careful to replace it correctly.
Step 5: Wash Keys
With a wet baby wipe (or a rag soak of glass cleaner) rub the keys strongly.
Step 6: You're Done
Sorry for my bad English, but I think it still understandable !