Ridding shoes of dampness from foot perspiration can help prevent odor and even lengthen the life of the shoes. So whenever you take off a pair of shoes for the day, slip a few small pieces of white chalk (or inexpensive children's sidewalk chalk) into each shoe to help absorb moisture.
For a tidy, efficient way to move the chalk pieces into and out of your shoes, consider wrapping them in small scraps of cheesecloth and tying the tiny bundles with twist ties.
Another easy way to help remove moisture (and odors) from the insides of shoes is to crumple up newspaper and stuff it inside the shoes when they are not being worn. Be sure to use fresh pieces of newspaper each time.
Whether you use newspaper, loose bits of chalk or the little, homemade shoe sachets, be sure you remember to remove them before you slip your feet back into the shoes!