I don't know about you, but my gear bag always smells like it has at least one dead animal in it. Where do you keep your stuff between training sessions? And how else do you counter the smell?
1) As soon as you get home, take your uniform out of the bag. If you can't / won't wash it between classes, then at least hang it so that it doesn't get wrinkled, and can also dry out quickly. Wet uniforms allow bacteria and other unpleasantries to grow and multiply, and the waste products they generate are foul-smelling indeed.
2) Take your hand pads, foot pads, cup and supporter, etc., out of the bag. Same reason as above.
3) Throw the bag in the washer. Add some color safe bleach, if possible. Let hang dry, or else it also becomes a breeding ground for the above mentioned microbes.
4) If you need to get rid of some really unpleasant smells that won't come out with a washing cycle, fill a container full of hot water. Add a small box of baking soda to the mix, which will first of all create an alkaline environment that will be unfavorable to many microbes, and second, absorb many odors / stenches that were trapped in your bag.
5) Get some Febreeze (if it's available in your area). Good odor killer, although this is only for a temporary thing.
Grenadier gave excellent advice, however, try a natural de-odorizer rather than Febreeze. I have severe reactions to it and so might your training partners - and it's arguably bad for you.
Clean your sparring equipment as soon as you possibly can - before you leave your training area if possible, if not, as soon as possible when you arrive home.
I use an old fabric softner sheet as a means of last defense...at least it keeps it smelling like "just washed" sweat instead of "been-in-the-bag-so-long-it's-starting-to-grow-appendages" type of thing..er yeah.
It's easier to have at 2-3 Dobak/Dogi in the laundry rotation though...dripping funk on your training partner is frowned upon in most schools/civilized nations.
wash everything in your bag that you used that night. if it smells, clean it. those little packets of silica gel that come in new pairs of shoes work great. hiding the smell doesn't do anything productive. odor and bacteria exist in moisture. kill the moisture, kill the smell.