10 ways to give a guitar with a polyurethane finish a "relic'd" or vintage appearancePreview1. Wear and tear: Use sandpaper, steel wool or a wire brush to simulate wear and tear on the body and neck of the guitar.2. Aging: Apply a vinegar or tea solution to the surface of the guitar to simulate aging and discoloration.3. Check marks: Simulate checking or cracks by lightly scoring the surface with a razor blade or other sharp tool.4. Chips: Use sandpaper or a razor blade to create small chips on the edges of the body or headstock.5. Scratches: Scratch the surface of the guitar with a metal file or sandpaper to simulate scratches.6. Dings: Use a hammer and nail to create small dings and dents on the body or headstock.7. Faux rust: Use a rust accelerator spray to create a faux rust effect on metal parts such as the tuning pegs and bridge.8. Hardware aging: Use a brass brush or steel wool to dull or age the finish on the hardware.9. Strap marks: Simulate the wear from a guitar strap by sanding the finish on the upper bout and near the strap button.10. Aged pickguard: Use sandpaper or a razor blade to create wear and tear on the pickguard.