When selecting metal frog decorations, the material and surface treatment are paramount. For outdoor garden use, prioritize iron or steel with powder-coated finishes or anti-rust paint to prevent corrosion from rain and humidity. For indoor luxury settings, look for brass or copper-plated finishes which offer a more refined aesthetic. Ensure the welding points are smooth and seamless to prevent injury and improve durability. If the product is intended for ponds, verify that the paint is non-toxic and eco-friendly to protect aquatic life.