Dryer vent black

Black stuff all around this dryer vent outside. I don’t know what that is and I promised my client I would do more research on what it is or why it is there. Anybody know why this black stuff is on the exterior wall near the dryer vent? Are they drying lots of black shirts or something lol?

Could it be blackmold from the moisture out of the vent?

is there an old gas dryer?

did you try to rub it ? did it come off. almost looks like overspray from the photo. very odd?

Bet they burnt something in the dryer.

electric currently in use

i did not try to rub it off. i guess i mistakenly thought it was so telling that someone on here would immediately know what it was. i can say that close up it DID look like over-spray or charred paint from around a very hot vent. i guess an electric dryer could cause fire as well. Do you think they are having over heating dryer problems with flames shooting out the wall and they don’t know about it?! not trying to be silly, just really couldn’t imagine what would cause this black stuff. it did not look like mold.

they must have burnt something like you suggest…

Likely a longshot but did you notice any similar discoloration around the HVAC vents or was the interior freshly painted. Could a home with heavy smokers cause the discoloration on the dryer vent.

Cigarette would be brown.

Looks like dirt…

The moisture coming out of the dryer vent might be collecting on the wall. Any dust, dirt, smoke, etc is going to stick to it.