What's wrong with wiping the blade clean on moss or grass then another dry wipe on your trouser leg or hankie once all the blood has been removed ? - blood being the main cause of rapid corrosion. I used carbon steel knives for years before stainless was on the knife market and never had a problem with rust - just take proper care of it - keep it clean and oil it. The oil can be removed on the moss before carrying out the gralloch.
Thanks ecoman. I've been wiping the blade clean and oiling it when I get home after cleaning, but still noticed that there were a couple of spots marking the blade. Not rust, just darker spots. I was worried they might become rust spots.