Hello Damoh,
You shouldn't have to rip the keys off.
On the back of most keyboards, you can remove all of the small screws to separate the upper half with just the keys and plastic frame from the bottom half with the circuit board. If the upper half has no wires or electrical components and is nothing but plastic, then you can simply just wash in under hot water to get it real clean. Just be sure to dry it thoroughly and let it sit to finish drying between the keys before reattaching it back to the bottom half of the keyboard.
Otherwise, you can use rubbing alcohol and a bunch of Q-tips.
Hope this helps,
Shawn