How can I keep my keyboard clean?

If you are unable to use a preventative mechanism like the covers described, then I suggest simple habits like the following, as they seem to work pretty well for me:

  1. Make sure you wash your hands before working with your keyboard -- this keeps loose dirt from falling off, mixing with your sweat, and turning into grime. Also, if you use your keyboard for prolonged periods of time, take breaks to simply go wash your hands of naturally occurring oil buildup. If you feel your fingers slightly oily on your keys, go wash your hands.
  2. Don't eat or drink over/near your keyboard. This really goes for anything crumbs that can fall off. Most people refuse to do this, and it's number 1 cause of buildup under your keys.
  3. Try to touch type with your fingers more raised rather than resting... like how typing teachers always preach. The pecking motion will prevent a lot of the transfer of dirt to your keyboard because it minimizes time and area of contact.
  4. Keep your hands dry. The raised finger "pecking" mentioned in #3 will improve airflow to your hands and dry them naturally, but you can also use a napkin, shirt sleeves, pant-legs etc to dry your hands.
  5. If you're really having trouble, consider wearing some thin gloves while you type or maybe even some coating on your fingertips like elmers white school glue. This sounds a bit too far to me, but some people really hate dirt. I'm not gonna judge you!

Good luck!