Use a utility knife to cut the lip from the aluminum tray. Working lengthwise, cut 2-inch-wide strips from the remaining bottom piece of the aluminum sheet. Cut the strips in half crosswise. Discard any strips embossed with the manufacturer's logo.
Finish the edges by placing a 1 1/2-inch-wide ruler along the center of the strip. Fold the edges over the sides of the ruler. Remove the ruler and burnish with a bone folder.
Use decorative edgers to make a paper template. Start with a piece of paper that's 1 1/4 inches wide and as long as the metal strip. Fold the paper in half, and cut along the non-folded sides with edgers. Unfold the paper. Place the paper template, backside up, onto a piece of scrap wood. Place the template over the aluminum strip, then tape the two in place on the wood. With a nail and tack hammer, tap the design into the metal, using the outline of the template as a guide. Try to keep the punch marks evenly spaced. Once you've finished punching your design, remove the template and metal strip from the scrap wood.
Use the ruler to fold over 1/4 inch on each short end, folding one end up and the other down. Form the strip into a cylinder by wrapping it around a rolling pin and interlocking the folded ends. Fold over one more time to secure. Use a pliers to crimp the fold.