The ones that really smell bad are my soccer clothes, but what i do is that i wash them as soon as i finish playing so that it's still wet and the smell isn't stuck in the fabric. i hand was the bad stains. that's about it.
That's a tricky one though! It sometimes messes up clothing.
Josh, you can do what the drycleaner does yourself.
Take the shirt (or whatever it is) and lay it on a table/ironing board or something similar. Then take a towel and soak it in clean, warm water then wring it out but not too much, you need it to be wet. Place the towel flat on the t-shirt (one layer, don't fold) and start ironing over it. The steam from the towel will clean the shirt.
It's not a miracle method, won't clean heavy stains etc. but it will probably remove most bad smells.
You can tell I've been living on my own for two years already can't you?