Organic cotton products are machine washable, but we recommend that you do not use "synthetic laundry detergent" or "fabric softener or "bleach" as much as possible. Our organic cotton has been produced to prevent chemicals from accumulating cotton flowers, processing and shipping. Using synthetic detergents may damage the quality of organic cotton and is not good for your dogs skin, so please use natural detergents as much as possible. (It does not mean that you cannot use regular laundry detergent) Since organic cotton products have not been treated with "shrink-shrunk" or "crease-stabilized" processing, it may shrink or warp after washing, please use a "washing machine bag" or set the machine to "weaken the running mode. Organic cotton does not "bleach" or "chemical wash" after product processing, so the product may have some "cotton scake" or "slight stains" that look like black garbage, but after washing, it becomes slightly invisible. Organic cotton products have no constant color tone or brightness. This is due to the temperature and humidity of cotton grown and the difference in the area of cultivation. Thank you for your understanding.