Beilstein Test with Christmas Lights

I have heard over the years about placing old Christmas lights into a campfire to make the flames turn green. This is a variation of the old Beilstein test for halogenated compounds, where copper metal reacts with halogens in a flame to turn the flame green.  In the case of the Christmas lights, the halogens are supplied by the chlorine in the polyvinyl chloride (PVC) insulation and the copper metal is supplied by the electrical wiring.  I tried this with a little bit of Christmas light wiring and the flame from a propane torch.  When the copper wire alone or PVC insulation alone was in the flame there was no green color, but where there was exposed wire near the insulation the flame turned green.