I take each and every key off the board, clean it with a cotton bud or somthing, then clean the area around the key where it goes on the board, then put it back in.
I do this to EVERY key.
And Yes, it takes FOREVER, but cleans it nice and good, my keyboard gets ALOT of use, and since i eat at my computer too, It gets quite messy, Somtimes so bad i cant press a key because too much food is laying beneath it