A sanitary case having a cavity defined by a bottom and perimeter wall extending upwardly from the bottom, at least one slot defined through the perimeter wall adjacent the bottom, and a liner disposed on the bottom. The food and spacer members are alternately placed into the hollow tube, in a similar orientation as coins are arranged in a roll of coins. At least a portion of the fluidized fine powder is then captured. Then, images to be laid out on a template are determined according to the importance degrees. Flexible decorative strands of material, having enlarged ends larger than the slot, can be slid into the opening of the slot and into the third section, where they remain unless deliberate manipulations are undertaken to remove the strands. This arrangement of the invention effectively increases the maximum flow rate of the negative pressure valve in the open position.