Karate Uniform Care:
Most Karate uniforms will shrink when washed in hot water, especially those made from cotton. Although the initial shrinking during the first wash/dry cycle is by far the greatest, it is generally recommended to wash your uniform in cold water as this greatly reduces the shrinking. Care must also be taken during the drying step. Tumble drying can cause uniforms to shrink to a point where it will no longer fit.
Be careful with the use of any type of bleach when washing your uniform. Over time, bleaching can severely weaken the uniform material, causing it to rip easily. Repeated bleaching may even cause small holes to appear in your uniform. Bleaching will also adversely affect the usually colorful badge that indicates your style and dojo. There is a product on the South African market called BioTex. I use this as a pre wash to keep my uniforms bright and white. Just check out there are two different kinds: one for automatic machines and another for hand wash only. If you do require to bleach your uniform from time to time, you should consider to use Velcro to attach any badges you have on your uniform. That way you can simply remove the badge when washing or bleaching your uniform and keep the badges looking brand new.
Most cotton and canvas uniforms, when washed in a washing machine on the drip-dry cycle, can be hung on the line without spin drying. This may in fact make ironing unnecessary. Just flatten the wet uniform with your hands once it's on the clothes line to remove the largest folds and wrinkles and it will look very smooth when dry. If you still prefer to iron, it will iron much easier when it is still slightly wet.