Here's a great tip I read in a money-saving ezine I get:

My two sons' sports bags, cleats, shin guards, etc. had a horrible odor that would smell up the car and the garage where we kept them. We tried expensive odor control pads for the shoes and fresheners for the bags and nothing worked. Now we have found a better and cheaper alternative that actually works!

First, buy activated charcoal from your pharmacist or home improvement store. Then wrap about a peach sized amount of the charcoal in a small square of cheesecloth. Gather the top of the cloth and twist. Attach a rubber band and keep in the sports bag. I make smaller sachets for school shoes and cleats. The sachets can be used over and over again. There is no "girlie" smell that is so foul to boys! It costs almost nothing and lasts a very long time!