You may have seen these very expensive bags that you place several pillows in or a duvet, then you attach your vacuum to the bag and suck all the air out. I bought some they cost me a fortune and the air kept leaking out. Well I saw the exact same thing done with a black trash/bin bag. You can use it on anything like pillows, blankets, duvets. Place them in the black bag and gather the open end up around the pipe on your vacuum cleaner. Suck all the air out and you will see that the mass of the item has decreased by about 90%. Simply wrap a rubber band around the end. When you undo the band the items will return to their original size.