My Sports bras are grey!

[papaver]

I've occasionally had some luck using baking soda (made into a paste with a little water, rubbed into the stains, and let it sit before laundering) on sweat stains. I've heard that adding a cupful of baking soda straight into the washing machine helps brighten things up, too, but I've never tried that.

Yep, that helps, along with washing your fabrics hot enough. (60 °C or 140 ° F). And I use plain vinegar as a fabricsoftener. It works a charm and it keeps the colors intact!

Oh yes one more thing: are you using your own washing machine or are you going to the laundry? When I lived in an appartment I always went to the laundry, and the machines there wash too fast. (max 45 mins or so). My washing machine does it in 120 mins... A HUGE difference. Everything went gray at the laundry.