Our insoles can be washed by hand, and the machine as well. We find that hand-washing will help preserve the longevity of your HIWALK insoles. I sometimes think of the shoes and insoles as a cotton sweater - can be washed, but over-washing can affect structure and lifespan.
For hand-washing, we typically suggest applying a small amount of gentle detergent to the top. You can rinse the detergent off in lukewarm or cold water. To target the odor of the insoles, we recommend putting a few drops of tea tree or eucalyptus oil and a bit of gentle detergent in a bowl of lukewarm water. You can then wet the tops of the insoles with this oil and water mixture. Rinse with lukewarm or cold water.
And last, but certainly not least, be sure to let the insoles air dry!