[Arran]

Ed;
It was very likely vinyl covered wire given the vintage of the set, there was some rubber/gutta percha wire used in sets in the immediate post war era whilst there were shortages of materials, but much of that was gone by around 1950. From late 1945 to 1947 or 48 there was a pent up demand for consumer goods of all sorts, particularly radios and cars, so some radio manufacturers were not only using war surplus parts for building sets but were using pre war surplus parts like dog bone resistors, and rubber/gutta percha wire for a while, along with field coil speakers, and even cloth covered power cords. This was what surprised me with that Bush DAC 90A I have, it was build in 1956 near as I can tell, but they used rubber/gutta percha wire, most of it is still good other then the wiring to the big ballast resistor, that was just not being used anymore in either American or Canadian stuff by then.
The stickiness is caused by the plasticizer leaching out of the vinyl, but usually doesn't harm the core of the wire, so what I and others have done is to wipe it down with mineral spirits, or naptha, on a rag or paper towel, and it comes right off along with the dirt that sticks to it. I think it really depends on whom supplied the wire as not all vinyl covered wire goes that way, I guess some just used too much plasticizer where others did not. Were these pilot lamp wires red by any chance?
Regards
Arran