This is AWESOME! It's cheap and easy, and it works like a charm. Wish I had a before picture of my tub. It had the nasty pink/orange crud all over--- scrubbing bubbles cleaner couldn't even cut through it! But the vinegar and dish soap did the trick. It's so clean now. :-)
How to Clean Window Tracks: white vinegar and baking soda (or hydrogen peroxide!) 30 Q-tips toothbrush hot water paper towels Sprinkle baking soda into the corners, then pour in some vinegar. The baking soda will begin to bubble and loosen up the cruddy stuff. When the bubbling calms down, begin to make circle motions with a Q-tip, then go back into the corners and sweep the muck towards the middle. Pour warm water from the corner to the center. Use your paper towels to wipe everything dry.