Re: Gi advice (judo/bjj/aikido)
When you train in high impact sports like wrestling, judo and bjj, you are in very close contact with the mat, and with very sweaty persons. Unfortunately, while you can bath yourself, normal washing (except in hot water, and with most gi's being made out of cotton, you can see why this is not done) does not always kill all the nastys that live in a your equipment. Some equipment can't even be washed (such as boxing gloves). There is a moderate chance of catching some nasty bacteria or virus sometime withing your training. I personally have gotten ringworm 3 times. I've also know someone who got a type of viral wart (molluscum).
This is why it is very important to wash your gi after every single class, and to spray all gear with cleaners, and wash all mats with anti fungal, bacterial, and viral cleaners. Recently, a new line of clothing has come out containing anti-microbial treatment. This is to stop the nasties from getting into the clothing, and thus in theory, helping keep you safe from infection. I personally have a few rash guards treated with this. I have no idea if it helps, but being a clean freak, I tend to use anything that makes me think I'm cleaner.
I have not found this to be a problem in aikido, the level of body contact is very minimal. A lot different then a very sweaty guy laying on you rubbing his sweat coated sleeve into your face.