First things first, put your ice/water dispenser on LOCK so it won't work when you press on it! Pour your vinegar into a bowl then rip off 4-5 pieces of paper towel and set them in. Poke them with a fork so they all soak up the vinegar.
Squeeze a bit of excess off and drape the paper towels all over your water dispenser, pushing it against the walls to get them to stick. Some dispensers you can take off the bottom pieces and can soak that part too.
Let sit for 5 minutes.
Take off and shine. If there are spots left, squeeze your lemon in a bowl, dip a toothbrush in it and shake some baking soda on top. Brush, brush, brush!