Silver reacts with its environment. A bright coin can tone at the rim, a bar can tarnish and some modern bullion coins develop cloudy white marks known as milk spots. None of these conditions automatically removes the silver content.
Natural toning
Toning can range from gray to vivid rainbow colors. Some collectors value attractive natural toning, while bullion buyers may treat it as neutral. Artificially induced color can be a concern.
Tarnish
Tarnish is a surface reaction, often involving sulfur compounds. It may darken silver without changing the underlying fine-metal weight in a meaningful way.
Milk spots
Milk spots are cloudy white marks associated with minting and cleaning processes on some bullion coins. They can reduce visual appeal and collector premium even when the coin remains genuine bullion.
Do not casually clean bullion
Abrasive cleaning can scratch surfaces and create an obviously altered appearance. For ordinary bullion, cleaning may do more harm than leaving stable toning alone.
Bullion is volatile, can trade below your purchase price, produces no income and creates storage, insurance and resale responsibilities. This page is educational and does not recommend a personal allocation.