if your dirt is completely dry, can you just put it and the shaved wax in the mixer and the friction will warm it enough to coat it ??

Never tried it but I doubt that would work. You need heat of some sort.

use a weed burner

You will need heat, weedburner works great. Wax needs to be around 130 degrees to melt. Not to much heat or you will scorch it. Buy a temp gun, they are cheap at places like Harbor Freight.

How do you all clean the mixer when all is said and done?

It is hard to get all the wax out. I just start using it again mixing cement and that seems to work ok