Vanessa: maybe these will help
Hi Vanessa: You can stack the milk crates 2 or 3 high, make 2 stacks and then put a board across the top for a shelf. You can even put 1 layer of milk crates and a board, and then a 2nd layer and another board, and so on. I wouldn't go too high as they may fall over. If you can get a thin piece of wood, maybe like the thickness of 2 paint stirrer sticks, and put them on the front edge of the milk crates, leaning them back towards the wall a bit, that will help keep them from falling forward. Heck, you can even glue 2 paint sitrrer sticks together:) So, you will need 4 total, 2 on each front edge.
Stack your crates like steps and place your boards across each step.
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