Get collections under control with a stack of storage containers. The clever latches — made with paper fasteners and recycled plastic caps — keep the contents secured inside.
Use the masking tape to seal the seams of the boxes, inside and out.
Paint the boxes with the foam brushes. Let the boxes dry.
On each box, measure and cut a door that's 1 inch in from three of the edges, using the fourth edge for a hinge. If your door is long and skinny, strengthen it by taping a smaller scrap piece of cardboard to the inside.
In each door, punch a hole for the knob 3/4 inch in from one edge.
For each knob, use the craft knife to make a small slit in the center of the 2 plastic milk caps and a 1- by 2-1/2-inch piece of scrap cardboard.
Thread a paper fastener through both caps, the hole in the door, and the scrap cardboard. Open the fastener arms so that they're flush against the scrap cardboard and secure them with the clear packing tape.
Close the door and turn the knob to latch it. With the thumbtack, mark the knob with a small dot next to the edge of the door to indicate the latched position.
Stack the boxes, attaching them to one another with double-sided foam tape. Make paper labels describing your cabinet's contents and mount the labels with loops of packing tape.