Should I clean coins I found metal detecting?
Verdict summary
Not old or possibly valuable coins: cleaning, rubbing or chemicals destroy the surface and can wipe out most of a coin's value. Rinse loose dirt off with plain water at most and identify it first. Modern everyday coins can be washed with mild soap and water.
Never use abrasives, wire brushes, vinegar, or polish on old coins. Silver and gold coins usually come out of the ground in good shape; copper and bronze corrode and should be left alone.
For archaeological finds, record where you found them before doing anything else.
Sources: Numismatic conservation guidance; Portable Antiquities Scheme advice to finders.
How do I identify an old coin I found? Look for the country, denomination, date and mint mark, then match the design in a coin catalogue. If the date is worn, the portrait, legend lettering, size and metal narrow it down. Free references include Numista and, for British finds, the Portable Antiquities Scheme database.
How do I know if my find is worth anything? Identify it first: value depends on exactly what it is, its date, condition and rarity. Gold and silver items are worth at least their metal content. For coins and jewellery a reputable dealer or auction house can value them; archaeological finds can be recorded by a museum or finds liaison officer.
Primary sources cited
- Numismatic conservation guidance
- Portable Antiquities Scheme advice to finders