Blades should be wiped dry after use. Carbon steel blades such as 80CRV2 and 1095 with a satin finish can be marked by finger prints if not wiped clean. Carbon steel kitchen knives with a satin finish are likely to form a patina with use.
Use a cutting board or other suitable cutting surface to avoid damaging the sharp edge. Avoid cutting on surfaces harder than the knife edge, such as ceramic plates.
I recommend a light coat of food-grade mineral oil or choji oil for storage.
If spot rust forms, remove the oxidation with an ultra fine 3M Scotch-Brite pad. First, wipe the blade completely dry and remove any oil. Next, abrade the oxidation with the pad wiping parallel to the length of the blade (can move back and forth). Avoid doing this with any oil of the blade, especially with the black oxide finish, as the abrasive particles can form a slurry with the oil as a cutting fluid and damage the finish of the knife. After removing any oxidation, wipe clean with alcohol and reapply oil.
Unless otherwise stated, knives are sharpened to a 20 degree angle on each side (40 degree edge, all inclusive). Many off-the-shelf field sharpeners and kitchen knife sharpeners are set to accommodate this angle.