rober, heat the wax, whatever method.....crockpot, double boiler, micro, yeah micro works long as you don't set it on fire........
get some of those inexpensive paint rollers, dip it in the wax, roll on, good to go.
i use the double boiler method, in the shop/garage on a hot plate so i can cover frames quickly and not worry about slops in the kitchen or 'waxing' my kitchen floor, or...... starting things on fire........
i have also done as apis suggested with a block of beeswax for stripped areas and cold rubbed on. for full frames of plastic foundation, (and i do use waxed peirco, i put extra on), i will run an extra layer of wax on.