Remove the laces from the shoes and set them aside. If they are stained, old, and frayed discard them and replace with new laces.
Remove old inserts from the sneakers and discard them. Replace old inserts with odor fighting inserts or new clean inserts.
Dip a toothbrush into warm soapy water. Dissolve 1 to 2 Tbsp. of powdered laundry detergent into 1 quart of warm water and use this solution with the brush to clean the shoes.
Wipe the shoes off with a damp cloth to remove residual soap.
Pour tea tree oil into a small spray bottle and mist the shoes inside and out. Tea tree oil is anti-fungal and will kill any lingering bacteria, which may cause odors.
Set the shoes in well ventilated area to dry. If the weather is nice, set them outside for a couple of hours.
Move the shoes indoors and sprinkle baking soda inside them. Leave the baking soda in the shoes at least overnight and dump it out in the morning.