The insulation on the headphones has become sticky. What happened to them?

Question

iPhone

I used standard headphones from an iPhone for a while, then I bought wireless ones, and I wound up my relatives and sent them to the phone box. They lay like that for a couple of years, today I got it, and the insulation has all become sticky. At the points of contact of the wire itself with itself, it generally turned yellow, and in the process of rubbing off this incomprehensibly sticky thing, it was completely erased and remained on a rag. Headphones among similar ones are of high quality, the box was in the closet, the humidity is normal, the sun's rays could not get in either.
The question is, why is this happening? What happened to them?

Answer 1

The plasticizer comes out of the shell. This is normal when the headphones are kept warm. Why is this happening? Because they were warm. Can it be prevented? You can store it in the refrigerator; D
But there will be little point in this, manufacturers are interested in breaking their equipment so that you come for it again.
On the Internet, I read, it is treated with alcohol and cotton wool, but you should not be zealous, because it is not known how these snot, which are now called "isolation", will behave with a high concentration of ethanol.
It will also not work for a very long time, because without a plasticizer it will lose elasticity, sooner or later it will burst and the wires will climb. Alas.