Choose white lithium grease when there's metal on metal contact. Purchase white lithium grease from a hardware store. There are numerous brands, most available in aerosol cans that are easy to use.
Move the part(s) so you have easy access. Remove mechanical parts to get good contact as you apply the lithium grease.
Spray the white lithium grease where needed (anywhere metal might come in contact with other metal). Watch it infiltrate small crevices and fill small spots.
Let the grease dry. Once dry it provides excellent lubrication and protection.
Wash your hands with a degreasing product after using.