If you want to go down the waxing route you need to completely strip off 100% of all grease/oil that's been previously applied. To do this naphtha is excellent, as is mineral spirits. A screw top gatorade bottle or similar is great for this sort of thing. Put the chain inside along with some clean solvent and shake like hell. Shake, rest, shake some more, over the course of 15 mins or so and then dump out the solvent into a different bottle (for recycling.) Add more fresh solvent and continue, but this time allow the chain so soak overnight. Shake, soak, continue. Do this until you are positive all the old lube is removed. At that point pull out the chain and hang it to dry out for several hours in the sun. After it's properly dry then you can go ahead with the wax treatment.