Achieving a smooth, polished finish on metal sculptures requires a combination of techniques tailored to the material and desired aesthetic. Here are the most effective methods:

1. Grinding and Sanding: Begin with coarse abrasives to remove imperfections, gradually progressing to finer grits. Wet sanding with lubricants like oil or water can enhance results for metals like bronze or stainless steel.

2. Buffing and Polishing: Use a buffing wheel with compounds (e.g., rouge or tripoli) to create a high-gloss finish. For intricate details, handheld polishing tools with felt tips are ideal.

3. Chemical Polishing: Acids or alkaline solutions can dissolve microscopic irregularities. This method is common for aluminum and copper alloys but requires proper safety measures.

4. Electropolishing: An electrochemical process that removes surface material uniformly, leaving a flawless, corrosion-resistant finish. Ideal for stainless steel and titanium.

5. Lapping and Honing: For ultra-smooth surfaces, use a lapping machine or honing paste to achieve mirror-like precision, often employed in high-end art pieces.

Each method demands patience and practice. Combining techniques—such as sanding followed by buffing—often yields the best results for professional-grade metal sculptures.