The first thing to try, provided the sneakers in question can handle it, is to machine-wash the shoes, possibly adding an odor eliminator like white vinegar or Zero Odor. You can also try a sports detergent (these are formulated to be especially good on very smelly things, because sports!) like Sport Suds. Removing the insoles and washing those can also help to freshen up a pair of sneakers that have turned rank.
When odors are developing, using an odor-eliminating spray like Kiwi Fresh Force or Dr. Scholl’s Odor X is a simple way to fix the problem in seconds. (Powders like Gold Bond, baby powder or baking soda also work, but they can be messy to apply, so skip them in favor of better options.)
To prevent odors before they happen, practice good foot hygiene, rotate your sneakers by leaving at least a day in between wearings, and consider using a set of sneaker balls to help eliminate smells while the shoes aren’t on your feet.
Protect your sneakers
Since we’re on the subject of prevention, a word on using protective sprays to keep dirt, road salt and pizza grease (oh yes, and you would be surprised how often I hear that one!) from staining a favorite pair of sneakers: You should use one.
Specifically, you should use one on suede sneakers, like Kiwi Suede & Nubuck Protector. Canvas sneakers, too — if you prefer that brand-new look to a broken-in one — will benefit from a protective coating, like Scotchgard Fabric & Upholstery Protector. The trick to using these sprays is to truly follow the manufacturer’s directive to hold the can six to eight inches from the shoe during application; it’s also a good idea to reapply the protective coating every 6 to 12 months.
A note on storage
One of the best things you can do for the health and good looks of your sneakers is to store them properly when you’re not wearing them. Tossing them in a heap, where they’re likely to become soiled and misshapen under the filth and weight of other shoes, is a good way to drastically shorten the life span of your sneakers. Storing sneakers in the box they came in, or in clear boxes that allow you to see the shoes inside, is a good option; using a shoe rack or bench is another way to prevent damage to sneakers while they aren’t being worn.
Another common sneaker affliction is creasing. Using shoe trees will help to reverse the natural creasing that occurs while wearing your favorite kicks and keep them looking, as true sneakerheads would say, fresh.