I agree, maybe stain removal should be incorporated into the chemistry curriculum? Might have actually remembered some of it then (Chemistry that is). I must say, I have found Latin tres useful as an adult (not).
BTW for curry stains, it is usually tumeric which causes the stain. Best cure for tumeric stains is sunlight, wash again, as per Anna's recipe, and hang out in direct sunlight, if it is sunny where you live. If you have enough sun it should magically 'bleach' out the tumeric stain.