Frankie,
Renaissance wax seems to be pretty good stuff. I bought a can a few years ago for use in the shop (woodworking). When I ran out, I didn't buy any more because of its cost. Plain old Minwax works as well as I need it to at a fraction of the cost.

I'd say use a good oil then wrap the knife well in saran wrap or some non-absorbant cloth ( i have no idea what that might be). When you need it, you can just wipe the oil off if you're unable to wash it, and it should be just fine for food prep. A little oil (that tiny film that remains), even if petroleum based, wouldn;t worry me during an emergency.