My machine dispensor is plastic and I have used vinegar for years. My Maytag washer and dryer are about 15 years old--had to get new ones when my others died at about 28 years of age. Just an FYI--fabric softener actually reduces the amount of moisture that towels can wick away, as it coats the fibers. Also, my repair guy says, fabric dryer sheets eventually coat the sensors in your dryer and cause it to overdry items.