Power cords turning oily.
 

Does anybody know what causes this? Is this the chemicals in the power cord breaking down? What can be done about it? ArmorAll?
Or is there something going on in my house that I don't know about.

It is probably excess plasticizer leaking out. Early plastic interconnect wire in 50's-70's TVs has a propensity towards this as does the wood grain vinyl covering on 70's-90's stereo equipment. Clean it off with rubbing alcohol or whatever works, and repeat when it eventually returns... Haven't seen the actual plastic harmed by giving off this substance its more of a nuisance than a problem.

To me it's more sticky and nasty, than oily. The RCA AM-FM tuner that you donated to the WARCI auction had a few interconnecting wires that are this way. I, generally use brake cleaner for the wiring.
I had some AC power cords that had green-goo leaching from the plug prongs and the interlock connector. :eek:

This also happens with '50's Western Electric desk telephones. The handset cord becomes oily and if it rests on the soft plastic housing too long it will make permanent marks in plastic.

I've seen a number of late plastic radio & even TV cabinets (polystyrene?) marred by an old cord resting on them for an extended period. I've seen that "goo" on HV wire & ultor cups; I also have one of those old hair dryers that uses a hose (handy for some projects, or warming up the bed in the winter :) ) and the hose is sticky with the stuff.

Old fashioned plastics breaking down. Ever see an old car with a sticky foggy windshield? First guess is it's driven by a heavy smoker. If not, it's probably the plasticizer evaporating out of the dash board under the hot sunlight. It is what it is, unfortunately. Polymers have come a long way.

Nasty goo or oiliness is usually the plasticisers from PVC. Sometimes green goo forms inside cables and works its way out at the terminals. Presumably a reaction with copper.

Never leave PVC in contact with polystyrene. The PVC will deplasticise and the polystyrene will dissolve. Expanded polystyrene will suffer very badly. Hard polystyrene, such as used in many sets of small drawers, will be marked.

As others have said, PVC cable can also mark other materials, such as some oiled or lacquered surfaces.

It can be a safety hazard where PVC insulated house wiring is in contact with expanded polystyrene thermal insulation.

Old PVC insulation may not be in the same rotten class as old rubber but sometimes it comes close.

I've had that green goo appear on the prongs of a plug on an old Hoover vacuum cleaner. Never seen it elsewhere. Clean it off and it comes back later.

I remember reading a manual for an appliance (I forget what, exactly) that stated the cord shouldn't be wrapped around the unit while storing, because it could leave marks. Only time I ever heard of that.

I've worked on many old radios that had the old plastic and or rubber power cords from the 1950s that had green goo leaked out of the prongs of the plug ends and even original cords on some of the old floor lamps from the 1940s.

I also have a mid 1950s Westinghouse Radio that the walnut Bakelite Cabinet and Black Bakelite Chassis and original rubber cord are in mint condition.

But the tuning knob which is supposed to be see through plastic (as the stations you are tuning in are seen through the knob) is all fogged up because of the plastic oxidizing.

The fog on the plastic tuning knob will clean off with regular soap and water, which makes the knob see through again but then about 2 or 3 months later the fog on the tuning knob is back.