surface preparation for finishing metals

• What is critical before applying a finish to a metal surface?

  Removal of dust, grease, and rust
• Why is it important to key the surface before applying a finish?

  To ensure the finish adheres properly
• What might happen if dust and grease are not removed before finishing?

  The finish may not adhere properly
• How does the need for grip affect the finishing process on metals?

  Some finishes require a keyed surface for adhesion