How to clean my wireless keyboard
You can clean these keys.  You need to lift up the individual keys from the bottom, there is a hinge that they click into at the top. DO NOT FORCE, they will come up. A guitar pick like device will helps. Once the keys are up, you can clean up the gunk underneath. 

The keys that are not square get pried up from the side, and some have small metal springs that may get lost if you're not careful.

Hope this helps.