Purchase a specialized coating to metal objects designed to protect metals against salt corrosion, such as ProtectaClear from EverBrite Coatings, KG Stock Kote from KG Industries, or Sprayon Welder's Stainless Steel Protective Coating from Krylon Industrial, all of which feature websites for ordering such products. Look for a protectant that is non-flammable, water-based and has been tested in a salt spray chamber for at least 2,000 hours, though 4,000 hours is preferable.
Pour your selected coating into a pan and saturate an applicator pad in the liquid. If you are working with stainless steel, apply xylene to the object's surface before applying the coating to remove all fingerprints and residue. Xylene also goes by the commercial name Xylol; purchase it through online stores such as The Nelson Paint Company, under the name Nelson Enamel Thinner. Klean-Strip is another brand of xylene; look for it at stores such as Lowe's, Sears and Big Paint Store, an online store, or try Painter's Pride brand of xylene, which can be purchased through online stores Eris Automotive Tools and Fox Run Tools.
Wipe the pad over the surface of the metal object in quick, straight lines. Use as many coats as needed depending on the type of metal you are working with. Refer to the coating manufacturer's instructions for best results. The coating should last for months if not years, depending on the brand you use.