Why can't a karate belt be washed?

You better, or you will be asked to leave the dojo! Yes, you can certainly wash a gi. Here are some things to help: Be careful of using bleach, it can wipe out the colors in patches. A colorfast bleach is safer. Turn the gi inside out when washing. Over time, the creases will wear through from washing if you don't. More important on heavy weight gi then a lightweight kid's gi. Pretreat any stains such as blood or sweat stains with a good spot detergent. Drying in the dryer can cause some shrinkage. Take it to a damp dry, and then hang to dry. The responsibility of taking care of the uniform is a part of learning to be a martial artist.