It has been a while since I do not clean my keyboard so I decided to wipe it clean. You just need:

Regular alcohol;
cotton balls, for instance;
a screw driver;
a paper napkin or serviette (US vs. UK) to put it under the keyboard so you will take all the mess when finish;
a brush (for painting; if you want you can get different sizes).

It will take you half of an hour approximately, it depends on how slow you want to go. Basically, you will need to remove all the keys, one by one, clean them, leave them to dry and once all the keys are removed of the keyboard, clean the keyboard itself. Then put the keys again on the keyboard. First, the qwerty and the FX, then the arrows and Insert, and finally, the numbers on the right.

Disclaimer: please do it under your entire responsibility, although I have included a video for you to see how easy it is remove of the keyboard the little keys, you have to be careful to not broke them, so be it!

Another disclaimer: this instructable can be modified to improve it, grammar and so.

Step 1: Removing the Keys.

Just place the screwdriver on the bottom of the key you want to remove and pry carefully in order to remove the key. Now you have two options, remove all at once or —the way I do it— remove one by one.

Step 2: Remove and Clean.

Take a little amount of cotton and pour some alcohol on it.

Take the key; no matter what method did you use, just take the keys with your thumb and index of the left hand and with your right one you rub the cotton until the grease and dirt are gone.

Step 3: Like the Chocolate Eggs, They Have a Surprise on the Inside.

Once you are done with the removing all the keys, surprise!!! you will have a really full of dirt keyboard. First, you take the brush and then you clean the inside with that. If you want an extra clean, you pass more cotton with alcohol. You will need it if the dirt is really sticked to the keyboard. If you have a cat or a dog you will have like a LOT of hair so your keyboard can actually suffers of fleas :D.

Step 4: Reassembling the Keys.

You only need to put the keys on the keyboard, again, carefully. Proceed as before with the arrows and Insert and then with the numbers on the right. You can pass a final time cotton with alcohol on the top and on the remain of the keyboard, I mean, the front and the back side.