The most common cleaner used is from a company called Caig. They make the DeOxit series of products. They have different versions, one for Contacts (input / output jacks, and one for Gold contacts) and one for Fader cleaning. Here is a link to their Website:
http://store.caig.com/s.nl/sc.2/category.293/.f
These products can be found at Guitar Center's, electronic stores, or most music retail webstores (Sweetwater, Full Compass, AMS, etc.)