The bin of a vacuum cleaner is simply where all the separated material is deposited, the larger the better as it reduces the frequency with which it needs to be emptied, the Mark I used a IKEA polypropylene bin, the Mark II used a builders bucket. Other ideas include, glass bowls, metal pedestal bins, cardboard boxes, resealable paint containers, and sealed fabric or plastic bags. Anything will do that holds it's shape under a vacuum, fabrics could be held apart using tent rods or a metal inner frame.