Do you have manly men, who work hard every day? Have you notice the perspiration-stained under the arms of there t-shirts? This is a cheap trick to remove the offending stains. Dissolve 5 tablespoons of salt in one litre of hot water. Sponge the garments with the solution and watch the stains disappear.
If the stain is really set in let the shirt soak about 20 min then wash
Oh this will work for the sweaty females in your home too.