Why avoid all liquids cdog? as long as they aren't water based they should be ok.
Electrical contact cleaner spray is a liquid, and can be obtained from the likes of Radio Shack, or similar!
A solvent such as white spirit or Turps may also work, but apply to a cloth and wipe rather than trying to pour onto the contacts.
Use only a natural fibre cloth (cotton) to avoid static.
Martin Vote if you found this post helpful please!!