Decaffeinated coffee works due to a discovery of phase changes in chemistry. Namely, very hot and very high pressure gases reach a state in which it no longer behaves as a liquid or a gas, but as a strange combination of both, capable of oozing through even solid materials. This phase is called "supercritical," because it occurs when a material is pressured and heated beyond a "critical point" that all materials have.
To decaffeinate coffee, the beans have supercritical carbon dioxide poured on them. The carbon dioxide can seep through the solid beans, and leeches the caffeine from within. After this, the pressure is removed, and the carbon dioxide evaporates as a gas. The caffeine is left at the bottom of the container as crystals, and the beans are ground into coffee. Coffee that has very little caffeine. More than none, but not enough to give a drinker even a slight buzz.
So, I was thinking, how about doing this with laundry? First a supercritical carbon dioxide bath, then a supercritical steam bath. Any oils, dirt, dust, or stains would be leeched from the clothes, and be deposited at the bottom of the container. Neither component pollutes when released (beyond how it came to be in the first place, but that's another story), and fewer resources are required than traditional washing. Also, the clothes are dried within 30 seconds, an advantage for quick turnaround. Sure, one would periodically have to clean the container, lest the oils build up until they immediately re-soil the clothes, but this should be a fairly trivial task if done regularly.
Unfortunately for me, somebody came up with this idea first, and patented it. So if I, or you, or someone else, were to build this, you would have to pay the holder money. Up until it expires in October of 2012.
In the meantime, I'll just have to supercritically clean other things, like perhaps my car, or my dishware, or bottles at the factory.