These pillows are all machine washable. Covered in a special German made 100% cotton that is also completely dust mite proof. There are no chemical finishes; just pure natural cotton that is specially woven to make it permanently down proof and mite proof even after repeated washings. It carries the symbol for German Quality Assurance, the Oeko® certification of purity, and SanProCare® which certifies that it is considerably more breathable than any other cotton. To achieve a sealed seam, there is no piping. Wash pillows separately, and only when soiled. A good quality machine washable (and dryable) pillow protector (Not included) is strongly recommended. It is much better to repeatedly launder a pillow protector rather than the pillow. Too many launderings will eventually reduce the loft of the down.