Creating distressed or aged metal surfaces is a popular technique in art, furniture design, and industrial aesthetics. Here are the most common methods to achieve that weathered, vintage look:

1. Chemical Oxidation: Using acids or oxidizing agents like vinegar or hydrogen peroxide accelerates rust formation, creating an authentic aged appearance.

2. Salt and Vinegar Solution: A mix of salt and vinegar sprayed onto metal induces controlled corrosion, perfect for rustic or industrial designs.

3. Dry Brushing: Applying paint lightly with a dry brush mimics natural wear, highlighting edges and crevices for a time-worn effect.

4. Sandblasting or Wire Brushing: Mechanical abrasion removes layers, exposing raw metal beneath for a naturally distressed texture.

5. Patina Solutions: Chemicals like liver of sulfur or ammonia fumes create unique green or blue oxidized finishes on copper or brass.

6. Heat Aging: Torching metal darkens its surface, adding depth and simulating years of exposure to the elements.

7. Wax or Sealant Overlay: Applying wax or sealant after distressing locks in the aged look while protecting the metal from further degradation.

Each technique offers distinct results, allowing for customization based on the desired level of weathering and metal type. Experimentation is key to achieving the perfect vintage aesthetic.