Cut the 32-inch, 2-inch by 4-inch board in half using a handsaw. Measure the length of the board to ensure the cut is exactly half. You will need two pieces of wood 16 inches in length.
Lay the two boards on a table so they are vertical to one another. Place the door hinge to the end of the boards. One end of the hinge will attach to the end of the bottom board while the other on the end of the top board. The two boards are now attached together.
Take the jar lids and place them on the table. Make sure the lids are in good condition and have no signs of rust. With a drill, make two holes in each jar lid. Place one lid on the inside of top board and one on the inside of the bottom board. Secure the lids using 1-inch wood screws through the drilled holes.
Fold the boards down so the lids rest inside the two pieces of wood. Place the screen door handle to the top board. Use a screwdriver to screw the handle in with the provided screws. If no screws are provided, use 1-inch wood screws. The handle allows for an easier grip on the crusher.
Use a stud finder to find a stud where the can crusher will rest. Hold the bottom board against the wall on the stud and use two 3-inch wood screws and a drill to secure the board. One screw should be planted near the top of the board and one toward the bottom for extra support.
Allow the top board (with the handle) to hang freely. Open the crusher and place cans inside between the jar lids. Grip the handle and push down to crush the can. Watch the bottom board over time, since crushing may cause screws to retract from the wall.