I’ve been having oil like stains on my laundry now on and off for over a year. At first I thought it was my washing machine, so I even got a NEW washing machine but I’m still getting the stains. I have tried different kinds of detergent from powder to liquid, pods to laundry sheets, HE soap, to virtually dry little soap. I don’t use fabric softener, I have cleaned my washer, used afresh, vinager. Hot/cold water. Not sure what else it could be. It is most visible on dark cotton clothing. I have had repairmen come and one said maybe it could be that my water heater needs to be cleaned outs another said maybe I need a water softener. Could it be something in my pipes???? My house is built in the early 60s copper pipes.