a long time ago Wayne Goddard had an article in Blade magazine about using wax on steel to prevent rust. Basically he set up a test of various waxes and oil on carbon steel and then left (brine) water to dry and see which rusted. Oil lost. Wax won. Now to be fair, oil lost the rust test when you wipe it off and don't leave a visible coating.
I thought that was crazy so I duplicated his tests. I took a piece of carbon steel, divided it into sections and applied different waxes and oil and let it rust over night. My results came out the same as his. Briwax beat them all. (I did these tests myself 5 years before I got into the supply business). In fact wax beat oil hands down.
I did not test any of the commercial oil based rust preventative products. I know there are some very good products out there. I just don't like one that leaves an oily residue on the metal.
Some day I'll have to set up another set of tests. I prefer wax as it is non-toxic and adds a nice luster to the metal.
I use wax on all of mine. Either
Ren wax or
Lustra wax (Briwax reorganized and stop selling that brand to the USA. Lustra wax is identical to Briwax).
If you are on a budget, try Johnson's floor paste wax. It works fairly well also.
For wax coating, wipe it on all over the entire knife. Let it get mostly dry and rub it off. Just like waxing a car with paste wax.