White shirts are the toughest clothing items to treat when they get stained. There is nothing that ruins a crisps white shirt more than a careless red wine stain on the collar. Even basic white T-shirts can get armpit stains that just seem to get darker with each wear. Although some stains will completely ruin the shirt, there are some techniques that can help fade the mishap. Depending on the substance and how long it has settled into the fabric, there might be a chance at reviving your white shirts.
Separate any silk, wool or spandex shirts from your pile, and put them aside to be treated professionally at the dry cleaners. Taking out the stain yourself would only ruin these types of fabrics.
Pre-soak the shirts with armpit stains in 1 cup detergent and 1 cup water (per shirt) for an hour before you wash them.
Apply a bleach pen to any shirts that have dark stains on them, and let the bleach set for a few minutes before you put them in the wash.
Wash the shirts in warm water with bleach.
Take shirts out of the wash and check to see if the stains are still present. If stains still exist, fill a bucket with water and white dye. Soak shirts in the dye for as long as recommended by the provided instructions.
Make sure to treat stains right away, since the longer they set, the harder it is to remove them. The best type of bleach is non-chlorine or a slow-acting one, like a 3 per cent peroxide solution. For most top-loading machines use 1 cup of bleach, 1 1/4 cup of bleach if the washing machine is industrial-sized and only 1/2 cup for front-loading machines.
Read the instructions on the bottle of bleach, and make sure to follow them carefully. Too much bleach easily can damage clothing. Make sure to put on gloves when using white dye, since the chemicals could burn your skin. Dye your shirts outside since the fumes are quite overpowering and should not be used in an enclosed area.