Creating weathered or oxidized metal surfaces is a popular technique in art, design, and industrial applications to achieve a vintage or industrial aesthetic. Here are the most common methods:

1. Chemical Aging: Using acids or oxidizing agents like vinegar, salt, or hydrogen peroxide to accelerate rust formation. This method creates authentic rust patterns quickly.

2. Paint Effects: Layering acrylic paints, stains, or specialized metallic finishes to mimic rust and oxidation. Dry brushing and sponging add texture.

3. Natural Weathering: Exposing metal to outdoor elements like rain and humidity over time for genuine patina. Ideal for sculptures and architectural pieces.

4. Electrolysis: A controlled rusting process using an electric current and electrolyte solution, producing uniform oxidation.

5. Abrasion Techniques: Sanding, scraping, or wire brushing to simulate wear and tear, often combined with paints or stains for depth.

Each technique offers unique results, allowing artists and designers to customize the level of weathering for their projects. Experimentation is key to achieving the desired aged metal look.