Don't know how Von is doing it but I use to do it for a sheath that I used to store my fish cleaning knife in in the tackle box. That first knife and sheath were all about experimenting. I learned the hard way the knife still needs to be dry before it goes back into the sheath! Also learned like any treatment to leather it has to be refreshed every so often.
For myself I always used a mix of 3 -1 ratio of, the following 3parts beeswax and 1 part paraffin wax! Actually at this moment I can't explain the why. However it was something I discovered if I used 100% beeswax there was a problem. However in my feeble mind I can't remember what the problem was!! See what old age does for you!!
As to the
how of hot waxing. I have done it two ways. Get the wax hot enough to spread with throw away paint brush. Then heat the sheath with heat gun. Being careful not to burn the leather. All you are looking for it to let as much as wax can soak into the leather as possible. Let it cool and buff of any excess with a soft cloth.
The other way is to heat to liquid the wax. Then let cool till just before it starts to congeal again. I have poured it inside the sheath and then after a bit pour it back out. I then dipped the outside of the sheath!
Any way you do it the leather will only take so much of the wax and the excess can be buffed off with a good soft cloth! The buffing actually helps to push it into the leather by the heat created by buffing!!