Make sure you have string, metal shears, needle-nose pliers, aluminum sheet metal of at least an inch in width, string, sandpaper, clothespins and food-safe metal adhesive prior to beginning.
Draw the outline of a Christmas tree, a star, an angel, a gingerbread man or any other shapes you desire. If you are not artistically inclined, download free clip art to use. In general, simple, bold drawings work best for cookie cutters.
Trace the outline of the shape with string, add an extra 1 1/2 inches of length, and cut the string. Trim the aluminum to the length of the string.
Using the drawing, bend the metal into shape. Simple curves can be done by hand. Use the needle-nose pliers to create sharper angles.
Sand both ends of the metal strip to allow the adhesive to adhere better. Knead the adhesive with your fingers, and apply to both ends. Press the ends together, and remove any extra putty. Clamp the ends together with a clothespin until dry, then wash by hand before use.