Mineral oil is probably the easiest and cheapest way to go. Any big box or drug store will have it. Get the stuff labeled for use as a lubricant or laxative, 100% food safe and non-toxic. 16 oz. should be less than $5 and will easily last for years. I have many different types of carbon steel knives and do not desire a patina on most of them. I only use it on the blades as it stays wet too long, gums up and attracts dirt and dust to use as a pivot lube. As others have stated, clean with soap and water or even gelled alcohol (germX, etc) after each use and it will be fine. I use mineral oil when the knife will be put up for a while. I live on the gulf coast close to the water and have had no rust problems. If food safety is not a concern the Marine Tuff Cloth is very hard to beat for corrosion protection.