My experience has been if the devit solution is on the back of the bottle it doesn’t melt, it gets crystalized looking and I can’t get it off. I am careful to only put it on the front of the bottle and I wipe dow the sides so there is minimal amout on the sides. I have never used the borax solution, perhaps it doesn’t do that. I bought devit spray and I paint it on with a small paint brush. It really makes a beautiful bottle.