We did a test run when first receiving it with the towels, comparing the already clean towels to the towels washed with the pureWash and no detergent. It seems that the original color came through. The darks were darker and the lights were lighter! My sister came back from a trip to Africa with musty clothes because they were packed while wet. The pureWash removed the odor! I do have one stubborn shirt that the musty smell just doesn't come off, but I am still very happy with the unit. There was also an issue of one of the ball valves having a slight leak, but Phil was able to have us sent a replacement one. Thanks again!