I heat the boots with a heat gun (air) and rub the wax on the heated leather until it melts and soaks in. I move on as each area takes up its fill. I repeat any areas that look dry.
The welts get lots of extra wax, also.
They stiffen up and require a little break-in, but a couple hours in warm weather will cure that quickly.
I also do not have good luck using straight wax over Sno-Seal or Mink Oil.
If you decide to melt it on the stove and brush it on to speed the delivery you need to realize how easy it is to light that stuff off.
