Hello, I have a tin of NikWax dubbing that I would like to apply to my issue boots to soften up the leather a bit. However they have been highly brush polished over several months. Can I spread it thinly on the inside of the boot, then allow it to soak in from there? There is no special coating on the inside that I can see and the leather is quite thin. Waterproofing isn't the primary aim here, I'm after softness. Or do I need to strip the polish off then apply it to the outside?