Using an appropriate cleaning fluid (for the type of the dirt and the material your keys are made of) shouldn't put your laptop at risk as long as you're careful. Don't spray fluids at your keyboard - instead, spray them on a piece of cleaning cloth, and use that to rub the keys clean. Don't make the cloth soaking wet, try a small amount of fluid first and only increase it if necessary. Obviously, turn the machine off and remove the battery before doing so. For increased security, wait 2 hours before re-inserting the battery; even if a small drop of fluid managed to squeeze itself into a position where it could cause trouble, it should have dried up by then.
In general, as long as a bit of common sense is applied, the risk of destroying a laptop by cleaning the keyboard is smaller than most people think. Nevertheless it's good to be careful. Some of the advice I gave above is like the typical advice "ground yourself before touching electronic parts" - in 99,9% of cases nothing happens if you don't do it, but for the 1-in-a-1000 case of bad luck, it's still a good idea to perform this basic precaution.
Edit: Also, when using a cleaning fluid for the first time, I recommend to test it with the maximal amount of pressure you're planning to apply, on a safe spot of the laptop surface that doesn't immediately strike the eye, and then test it on a non-important key. Again, this precaution usually isn't necessary, but there are combinations that can damage the upper layer of the case painting and/or the color of the characters printed on the keys, especially if cheap materials were used. Since it's practically no additional effort to perform the test procedure I just described, I recommend to apply it.
Post edited March 11, 2012 by Psyringe