Flitz Ceramic Sealant is a very effective solution for long term storage of carbon steel knives. It protects against oxidation from the elements, whether in storage or on display.
Spray onto an applicator, such as a cotton round, and wipe in long, sweeping motions along the length of the blade. Before the sealant dries, buff with a clean microfiber towel to blend into a smooth finish. It dries completely transparent.