Good quality silk can go in the washing machine at 40 degrees in wash bags (although where I live it is not normal to use tumble driers, we just hang clothes outside or on radiators. So I do not lose any time by hang drying silk because I do it with all my clothes anyway). Never had the shrinking issue with cotton interestingly, but do find cotton/elastic blends are not as durable as more synthetic options. Cotton is something that can have wildly varying qualities and be constructed in completely different ways. I hate wool to be honest. And most linen I have come across has been weirdly see-through? Although linen is good upholstery material in my opinion.