Alkali washing cleans coins but it can do little for environmental staining. This guide covers the chemistry behind burial corrosion on silver and walks through a tiered treatment series — from sodium thiosulfate to rotary tumbling — designed to reduce the visuals of staining while preserving what the coin has left.

Learn how to safely and effectively restore ground find copper, silver, and gold coins. In this post I show how an Alkali Wash can be used to remove build-up from a coin’s surface. I always recommend testing on worthless coins to understand how the process works and may impact your coins. It is entirely your decision to use this process on coins that may have value.