Make your t-shirts are not yellowing and do not become gray after washing, wash it separately from bright and colorful things. If it is composed of linen or cotton, wash separately from wool and synthetics. During washing in the washing machine to powder, add powdered bleach or pour bleach into the compartment for pre-wash. Be sure to look at the packaging. These tools must be suitable for use in an automatic washing machine and for washing white.
If you are afraid to use bleach, remember how a few decades ago coped with the problem of bleaching white things. At that time it was very popular boiling with white. This method will fit you only if your shirt is cotton. In 10 liters of water, add 500 grams of soda ash and 500 grams of chlorine. Solution leave for two days, then strain. Boil the shirt in this solution for at least two hours. But be aware that this method of whitening leads to the rapid release of tissue failure. And there are more gentle ways.
Also bleach t-shirt using potassium permanganate. Add in a bucket with hot water and a small amount of potassium permanganate to the water acquired a pale pink hue, and 200 grams of conventional washing powder. Then lower the bucket already washed the thing, top cover with polythene and wait until cool water. After this procedure, thoroughly rinse the shirt.
Still glaring whiteness of your belongings will help return the solution of hydrogen peroxide. A bucket or basin, fill with warm water and add hydrogen peroxide per 2 litres of water one teaspoon of 3% hydrogen peroxide. Add a handful of baking soda. The resulting solution down the t-shirt for 20 minutes. That bleaching was uniform, the thing periodically stir.
Before washing, soak the shirt for a couple of hours in the water with ammonia. It gives the underwear yellowing and softens the water. If the thing is very dirty, add 3 teaspoons of turpentine.
To emphasize the whiteness of the shirt, use blue dye powder. Put it in 4 layers of cheesecloth and drop into the cool water. Remove cheesecloth after water is painted in rich color. Then the solution stir and dip into it white.