I have several different cleaning solutions and tools, depending on the type of grime in question. Apply the cleaning solution to the cloth or swab, not on the keyboard. Usually it works best to apply the cleaning solution to a set of keys, then come back along to clean that set of keys thoroughly.
- For typical grimy college student keyboards (when the keyboards are grimy, not the college or student), I use a vacuum cleaner followed by Windex and a cotton or microfiber cloth.
- For tobacco stains and other unfettered nastiness, I use a solution of alcohol (70% isopropyl) and "Arm & Hammer Baking Soda Washing Powder" on cotton swabs. You can substitute a mixture of any laundry soap and either baking soda (sodium bicarbonate) or washing soda (sodium carbonate). Use about a teaspoon of the powder for a half liter of the alcohol. The washing powder dissolves in the water rather than the alcohol, so it may be necessary to dilute with more water. The soda also has a mechanical cleaning feature if it isn't fully dissolved, but the trade off is more residue. Be sure to wipe thoroughly to remove any residue.
- I've also used Scope (20% alcohol with menthol and eucalyptus, I think) or Listerine (27% alcohol) instead of rubbing alcohol. The washing powder dissolves better, but there's not as much alcohol in the mix when mouthwash is used. This method leaves a clean, fresh scent.
- For some other icky types of pernicious goo, the pumice + citrus hand cleaners work great (but tend to wear away at the paint on the keycaps). Follow this with Windex, alcohol, or water to remove any residue.
Another approach is to flood the bottom of a shallow baking pan with some mild cleaning solution (so that only the tops of the keys on the keyboard will get wet) and carefully put the keyboard face down into it. After a few minutes, while keeping the keyboard face down, raise it out of the pan, shake it lightly and let it drain until drops stop falling, and pat out any excess cleaning solution using something absorbent, such as a cloth or damp sponge. Proceed as above, though your work should be easier.