In the Ripley's Believe or Not Department...
No Timmy, don't stick that keyboard in the dishwasher!
Apparently dishwashing filthy keyboards is becoming something of a rage.
Personally, as someone with a background in electronics, I would have never considered it - at least not until I read this article, and I was willing to junk the keyboard afterwards. If you do put your keyboard in the dishwasher, it is quite likely to become non-functional afterwards.
Mind you, there is a way to reduce the risk.
Frankly, you are better off to take a toothbrush and a bottle of rubbing alcohol to the keyboard, but if you really want to try the "quick fix", and you fully realize that you will likely have to toss a (now clean looking) keyboard away... you can try the following.
Neither I nor Neoseeker endorse the following method, if you decide to try it, expect to destroy your keyboard.
First, run a cycle with the dishwasher empty - this is to reduce the residue from past detergent runs.
Next, put the keyboard in, and run it on the "gentle" cycle.
DO NOT USE ANY DETERGENT / DISHWASHER SOAP / SPOT REMOVER!
If you are willing to risk the keyboard to water, you may as well let the dishwasher dry it.
Resist the temptation to plug the (now clean) keyboard in. Let it air dry for at least one day.
Try it after at least 24h on an unimportant computer - just in case something went badly wrong and the keyboard fries the PC (very unlikely, but not quite impossible).
It may work.
It may not.
But it will be clean :-)
Better yet, go spend $10 on a brand new keyboard.