My only question would be is the Xylene harmful to the O (or X) rings in the chain? I know it will dissolve most anything. Drop a piece of Styrofoam in it and watch it disappear. I heated up my chain with a heat gun just enough to soften the wax and then used kerosene on a rag to get it off which is definitely more time consuming.
I simple google search will yield your answer from Wiki.. What you want is 'limited' exposure to rubber and plastics. So the smart application of use would be to quickly use a rag and solvent ( as we called it in the old days ) to remove the wax from the chain. ALWAYS WEAR rubber protective gloves and work in well ventilated area. After removal of the wax, wash the drive line and areas you might have got this chemical on. Proper washing will reduce and further effects of usage on the chain that way. Dont just leave the chemical on the chain and go ride.
Solvent applications and industrial purposes
Xylene is used as a solvent. In this application, with a mixture of isomers, it is often referred to as xylenes or xylol. Solvent xylene often contains a small percentage of ethylbenzene. Like the individual isomers, the mixture is colorless, sweet-smelling, and highly flammable. Areas of application include the printing, rubber, and leather industries. It is a common component of ink, rubber, and adhesives. In thinning paints and varnishes, it can be substituted for toluene where slower drying is desired, and thus is used by conservators of art objects in solubility testing. Similarly it is a cleaning agent, e.g., for steel, silicon wafers, and integrated circuits. In dentistry, xylene can be used to dissolve gutta percha, a material used for endodontics (root canal treatments). In the petroleum industry, xylene is also a frequent component of paraffin solvents, used when the tubing becomes clogged with paraffin wax. For similar reasons, it is often the active ingredient in commercial products for ear wax (cerumen) removal.(1)