Use OxiClean. Use a cup of Oxi + 3 gallons of HOT water, soak uniform overnight. Done.
Use a thick t-shirt, and don't use antiperspirants. The antipirspirants are the culprit for the deep ugly yellow stains, because it is repelling the water used to clean. If this is your case, use a stiff nylon brush, some straight pine sol, and scrub the stains away. The pine sol is strong, so use it in a ventilated area. Do it on a clean counter so you have room to work. Don't worry, the pine sol is itself a cleaning agent, so the counter/table will get clean - but don't do this on a wood top, only laminate or some other safe surface. Rinse well, then use the OxiClean.
Some Adidas uniforms are made with cloth black v-neck material, some is made with nylon. Bleach is safe with the nylon, but, the uniform itself won't stand up well to the bleach - even the white part. So if you have a nylon v-neck, you can use bleach once in a while, but better to consistently use OxiClean.
EDIT: Yes, borax is good - but they have different effects. Borax is a water softener, which is needed if you have high mineral content in your water - hard water contains extra ions which prevent the surfactants in the detergents from working effectively. But it is not a good bleach, and sodium percarbonate (OxiClean) is excellent at removing organic stains - the very things that get onto a martial arts uniform, like sweat and blood. It works by binding with water molecules to form hydrogen peroxide, which is unstable and releases oxygen - this is the bleaching effect.
If you are removing dirt, then, borax added to a regular detergent is best if you have hard water, and useless if you already have soft water.
If you are removing stains, then pure OxiClean + water soak is best first, then a regular wash (with or without borax, since the uniform is probably mostly clean anyway.)
I would never recommend washing anything alone, except if the clothing were gentle clothes; you need the friction of the other clothes rubbing against each other for effective washing. This rubs away dirt as well as allows the surfactants to get inside the fabric. Without the rubbing action, you're only rinsing the clothes - not washing. You NEED the abrasion.
So a gi alone is never as effective as a gi + other clothes. Of course, there is a sweet spot, too - you don't want to overload, either, because too much clothes reduces friction and wears down your washing machine. So, for a gi, I would add the equivalent of 3 or 4 pairs of pants. Don't use towels, because they have a tendency to strangle other clothes, which reduces or prevents the abrasion needed in the rubbing action required to get the surfactants inside the material.
EDIT: Yeah, Cheer also works, but, I don't like using OxiClean as a washing aid, I prefer it as a soaking aid. I think - I could be wrong - but I think the way machines are built today are for water conservation and they don't lend themselves well to using a detergent containing an ingredient that is better suited for soaking. Yes, they have soak cycles, and it is best to use Oxi only for these cycles. But manufacturers seem to be riding on this OxiClean bandwagon for regular wash, but, I don't think it's the best or most appropriate use. The OxiClean that is inside detergent has already come in contact with water, and so has already given up it's hydrogen peroxide - which is unstable, and turns in to pure water and gives off oxygen. So while being highly environmentally friendly, it does nothing for your wash - or wallet.
I've had my adidas tkd uniform for a long time and it just started looking a bit dingy and yellowish even though I wash it after a few wears (don't worry I wear a shirt underneath). I assume it's from all the sweat that has made it's way through my undershirt to the uniform. It hasn't fully come out after I washed it. I generally hang up my all white tkd uniform in the sun after use since the sunlight naturally whitens. This uniform has a black v neck however and it's my nicest uniform so I don't want to fade the black v neck. Is there a way for me to whiten the uniform without fading the black part or the logos or damage the patch I have on it? Would it be safe for me to put that uniform out in the sun anyways? I know putting it in the sun a few times won't do anything but I don't want to fade it faster over time. Anyone who has the same style uniform who has found a way to overcome this problem, let me know!
