I have use Cream of Tartar to remove rust stains, but not mixed with bleach. This is the formula I used and it worked very well.

Make a paste by mixing equal amounts of cream of tartar and salt with hot water. Rub the paste into the rust and let it set for 15 minutes. Wash with your regular laundry detergent.

I have not used this on colored fabrics only on whites so I don't know what effect it would have on the colors.

Glycerine is magic, too... it will take wine stains and meat juices out of tablecloths and napkins. I used to leave my soiled linens on the table overnight, after having rubbed glycerine into all the stains. The next day, I washed them and you'd never have believed they had been badly stained.

I love what we learn on the board!