The jacket, trousers and belt that make up the basic karate uniform, formally called a gi, are usually made of a heavy canvas cotton or cotton-blend material. The traditional gi is white, although some dojos (karate schools) prefer to wear other colours. Sweat and body oil are absorbed into the material every time you work out, so it is important that you clean your gi properly to maintain its colour, shape and durability.
Remove your gi from your gym bag as soon as possible after training, even if you are not ready to put it in the wash. The longer the gi remains wet with sweat, the harder it will be to get clean. Airing it out reduces the potential for sweat stains.
Soak your jacket and trousers before running them through the wash cycle. Fill your washing machine with water and mild washing powder. When the detergent is dissolved, soak your karate uniform for 15 to 20 minutes. Do not wash the belt. Unless the belt has become exceptionally grimy or has come in contact with a rancid substance, it is against martial arts tradition to wash it.
Place some towels or other soft items inside the washing machine with your gi. This decreases the amount of friction the heavy canvas will create when it bounces through the wash cycle, which puts less stress on the stitching.
Run the washing machine through its complete wash cycle.
Take your gi out of the washing machine immediately after the wash cycle is complete and hang it up to dry. The wet gi should not remain in the machine for an extended period of time.
Do not use a mechanical dryer while the gi is soaking wet. Some martial artists never use dryers because the thrashing of a tumbler can be hard on the canvas material. If you use a dryer, wait until the gi has air-dried for a while and the fabric is slightly damp. Wash your gi after every workout. Although it might not look dirty, bacteria quickly builds up in the fabric. This is not only unsanitary, it can create an embarrassing odour when you sweat during your next training session.
Do not add bleach to your detergent when washing your karate uniform. Although it will make your gi look whiter, bleach will weaken the stitching and eat away at the fabric, making it easy to rip.