This is an Experiment They do not, it could damage your hat. This is just an experiment to test the effect of oxygen to a hat. In this case, the result was good. That does not mean this will work for other hats as well .. You could ruin your hat so. I have an old hat Wegener from 1967. Dusty, stained, he really needs a cleaning. Here I use lye water. The medium is based on an oxygen. Attention. Oxigen can bleach out. Please read the note from Art. http://www.thefedoralounge.com/show...r-vs.-Naptha&p=1394681&viewfull=1#post1394681 I suppose warm water. Using a measuring cup full of Oxy Clean. You see, the agent reacts immediately.