Many swear by CAIG DeoxIT. I personally use the imitation De-Ox-Id from GC Electronics because my local electronics supply store carries it and have always had great results with vintage audio equipment and TVs. I think it costs a little less than DeoxIT also. Many also use WD-40 but it leaves a residue which may attract dust and recontaminate the contacts, so I wouldn't recommend that. I used to use the contact cleaner from RadioShack but have had more problems with recontamination than with De-Ox-Id.