Request a Salt Spray Test report (typically 240+ hours) to evaluate the durability of the silver coating against oxidation. Conduct a cross-cut test on the protective back paint to ensure proper adhesion. For bulk orders, insist on a Pre-Shipment Inspection (PSI) focusing on edge grinding quality (e.g., polished, beveled, or seamed edges) and the absence of black spots, bubbles, or scratches. Utilizing a professional platform like Made-in-China.com allows you to filter for Audited Suppliers who have undergone third-party verification.