Dryer is leaving black marks on cloths.

I have the same problem. We think it is because the barrel is out of balance and the clothes are getting stuck between the barrel and the housingand the grease is causing the black marks. But I dont know how to fix that.

Was a pen or crayon placed in the machine by mistake ? You will need to
remove the residue, use rubbing alcohol on a rag for marker or pen ink , crayon use a razor scraper and then clenser and scrunge pad.