85. Which of the following methods should be used to dress the face of silver-plated contacts?

Sanding with 400 grit sandpaper is the correct method to lightly smooth silver-plated contacts, minimizing metal removal and avoiding damage to the thin plating. Other methods, such as filing or knurling, are too aggressive and would remove excessive material. While burnishing tools are often preferred in practice, this option best aligns with the exam's focus on a minimally invasive approach among the choices provided.