answer:As far as different washing intructions on items that are the same fabric, sometimes manufacturers put in dry clean recommended as a failsafe. Meaning there is less likelihood something will go wrong if you dry clean it, but you can wash it in soap and water. I have seen dry clean labels on polyester, which is ridiculous. Many cotton things, like cotton sweaters, you can machine wash, but need to be very careul not to shrink the garment and it may not look the same afterwards, same with silk. They might lose their shape a little. Athough, both often you can wash them and lie flat to dry. I have seen rayon items that are labeled machine was, and my recommendation is never wash rayon, always dry clean, I always kick myself when rayon gets into my washing machine by accident. In fact, I hate rayon! I try not to buy it at all. They use that fabric for everything now, drives me crazy. I’m interested to see what jellies say about the first part of your question, I don’t know the answer. I guess the chemicals and heat maybe kill off any germs? I really have no idea and I do want to know.