THE ONLY STAIN REMOVER YOU WILL EVER NEED!!!! Mix 1 part DAWN Dishwashing Liquid with 2 parts HYDROGEN PEROXIDE (which I already have for making Miracle Cleaner with). For stubborn stains or for items that still have a stain after being laundered (including having gone thru a dryer already) USE some Baking Soda for the extra scrubbing element by spraying mixture first and then adding the baking soda on top of the spray and scrub. Let sit for 1 hour and then wash. The stain should be gone!
**did this on 3/23/13** IT WORKS!!! then cleaned the whole carpet by putting white vinegar instead of shampoo in the machine...my carpet looks new...WOW How to Clean Stubborn Carpet Stains with an Iron and Vinegar/Water Solution: Spray carpet with solution. Lay damp cloth over spot. Iron over it with steam iron. Stain is gone! This REALLY works!
The first thing I did was sprinkle a bit of baking soda into the corners, then I poured a bit of vinegar/hydrogen peroxide into a cup and poured it into the tracks. The baking soda will begin to bubble and loosen up the caked on cruddy stuff.