What are these black stains coming from my Majesty Palm?

How can I remove them from upholstery? I have two Majesty Palms which are located in my living room where they have Southern exposure through a large bay window. I water the plant once the soil has thoroughly dried & I mist it twice a week. I’ve recently noticed that when the leaves begin to need pruning (they turn yellow, then brown, then I prune them) they are leaving an oily, black residue on my walls as well as my couch! Is this normal for the dying leaves? How can I safely remove the stains from my couch (microfiber, beige)? I’ve realized that to remove the stains from the walls I’m best off using a dry paper towel & rubbing them off which I know will not work on the couch. I hope someone else knows what I am talking about & can help me out. I am not looking for advice on how to care for my plant, so please only answer if you know what these oil drops are & how I may remove. Thanks!!