Mesh covers work wonderfully for outdoor lights, though the copper or brass will tarnish and darken over time unless treated with a weatherproof finish.
Steps 3 and 4: Unfold, then fold again in the opposite direction. Snip again in the middle. This makes a pyramid shape with an X cut in the center. Slip the X over the bulb and squeeze into place.
Steps 1 and 2: Using tin snips or scissors, cut the mesh into 2 inch squares. Fold the square in half on the diagonal and make a snip in the middle about 1⁄4-inch deep.