Black stains - what are they?

[Monaco]

What are these black stains? No candles have been near here. The wires never touch the wooden door/wall.

 

[JohnD]

Stand back and take some wider pics of the whole wall. Might be a TV and its cables. Or an internet hub. Or hifi.

 

[Monaco]

Here is a photo taken about a year- layout hasn’t changed (I’m not home at the moment to take a more recent photo). The black stains are on the cupboard door, and one of the photos is taken on the wall above the box cupboard. Inside that box is the gas meter and gas pipes- no pipe is touching or near the cupboard door

 

[RandomGrinch]

Hi,

I would say it's definitely marks related to the cables.
I suspect (and I may be wrong! ), that the darker marks are from soot (from candles/fireplace?), that has been attracted (electro-magnetically? convectively by warm cable?) and deposited on the wall in the vicinity of a cable.
I believe the lighter marks may be where the cable has actually touched the surface, and wiped away the soot!

Here is an example from another forum!
https://www.avsforum.com/threads/black-marks-on-wall.3173454/

 

[JohnD]

Black dust marks are common around TVs and their cables, due to static electricity buildups.

Some other electrical and electronic equipment, including PCs and air purifiers.

The later pic shows the corner to be crammed with such equipment.

The dust is so fine it migrates into paint, and is very difficult to clean off.

 

[Monaco]

Thank you for your help!