If you have the time, a box large enough and deep enough to allow you to put in some cedar pet bedding, then the knife, then cover it completely with cedar. I have two leather handled Schrades hunters that unfortunately found themselves in a musty dank cellar for about 40 years after I left my folks home, recently recovered them, the dirt smell would knock you out. I washed them well with antibacterial dish soap, dried them with a rag, then into the cedar. 3 days later, no more smell, other than cedar. I also use the same method for leather sheaths, and anything else that gets stinky. The wife and I refinish old furniture rather than buy new, and sometimes the junk we get stinks so bad you cannot breathe. A month packed with the cedar chips, no more odor.
Try it, see if it works.