Goo Gone. I bought one and took it off before the first load was finished. The odor was so string it hit me right in the asthma and started an attack!
I rarely use any kind of softener. Liquid coats fabrics so towels don't absorb as well. Following that line of thought, when my kids were small in NH (1970s) I would put their nylon snowsuits in the washer with a full 2 cups of softener. It waterproofed the suits for snow play.