Keep your blades in shape!
All blades are high carbon steel and will rust when they encounter moisture and acids from hands and the environment!
Use a little petroleum type gun oil or vegetable oil and lightly coat, especially if blade is touched or encouters moist or wet environments. Some collectors like bees wax, such as that used on Samurai swords.
Exotic woods can be rubbed with vegetable oil (not petroleum oils!) and left to sit overnight, then excess oil rubbedd off.