We recommend simply wiping them with a clean soft cloth. A little clean water may help to remove more stubborn dirt, but be sure to dry them with another cloth. We donโt recommend using any harsh cleaners or abrasives as these can damage the materials. We sell a leather care and conditioning kit here: http://www.audeze.com/node/174 however we donโt recommend using that on our leather-free products or the sides of our leather earpads because it may cause premature wear.