I put mine in the washing machine, 'it got them really clean', 'I like to hear that soapy water slosh', 'come on baby, let's do the wash' --- but seriously, the foam rubber backing (which was coming apart anyway) disintegrated, but who cares, the mats were spotless and now they lay perfectly flat. But I'd make that the point of last resort. I used 409 carpet cleaner and a towel (and elbow grease) on the rear mats and those fancy-schmancy foot rest thingies and it worked perfectly, too!