After the dye has soaked into the shirt, rinse it by hand under cold water. Once most of the excess dye has been washed out, switch to warm water and wash the shirt gently for several more minutes.
After the first wash, transfer the shirt to the washing machine. Wash the garment in cold water by itself. In addition to normal detergent, add ¼ cup of a professional textile detergent, such as Synthrapol. This detergent prevents the colors from running.
After washing by hand and by machine, the shirt can be dried normally in a dryer or by laying it flat.