Although Apple rejected this simple toll and dismissed it for not being very useful, I think that this KeyboardCleanTool is actually VERY useful.

I don’t know how often you clean your Mac’s keyboard, but I work with it, eat on it, and I generally clean it once a week. What happens if you clean it while your Mac is powered on? Everything you can possibly imagine…and not…and you don’t want to take a chance.
I know what you’re thinking…why not turning your computer off? If you are anything like me and work on 9 different desktops with 3 browsers constantly open plus iTunes, TextEdit, Skitch, Skype, Pages, Preview, Mail, etc…it’s a pain in the butt to shut everything down to clean the computer!

KeyboardCleanTool simply locks your keyboard and allows you to clean without having to worry to delete, do/undo something.

After installing the free tool, you’ll see the one and only button that you need to lock and once you’ve cleaned, you click again to unlock.

Download KeyboardCleanTool by heading to the developer’s page HERE

(Via)