Let’s say you want to decorate an all black surface, without damaging it deeply. If engraving and sharpies aren’t within your acceptable option set, I suggest duct-tape and an exact-o knife.
Begin covering your surface with a duct tape canvas. Next, sketch your desired design on some paper (I suggest graph paper) and secure each piece of paper with scotch tape.
Piece by piece, cut rectangles and triangles out from your design. Use the exact-o knife edge to help peel the severed duct tape from the universe set.
Repeat this process for each piece of your design. By segmenting your design, you can stabilize the paper “stencils” with tape more effectively than if you used one huge stencil.
After extracting the desired duct tape to form your pattern, trim the edges of your canvas to finish your decoration.
Happy decorating! This trombone case now complements my trombone’s design.