Metal Detecting and Coin Finds: What to Do with Your Discovery

Finding a coin with a metal detector is one of those genuinely thrilling moments that keeps hobbyists going through muddy fields and grey afternoons. Whether you have just pulled a corroded disc from a ploughed field in Suffolk or uncovered a gleaming Victorian penny on a permitted beach in Cornwall, what you do next matters enormously. The steps you take in the first few minutes – and the weeks that follow – will determine whether your find becomes a properly recorded piece of British history or a missed opportunity.

This guide is written for those who are new to metal detecting or coin collecting in the UK, and it covers everything from the moment you hear that tell-tale signal to cleaning, identifying, recording, and potentially reporting your find to the relevant authorities. British law is specific on this subject, and ignoring it can carry serious legal consequences. The good news is that doing things properly is not complicated once you understand the process.

Before You Even Go Out: Permissions and the Law

It is worth establishing the legal foundation before discussing what to do with a find, because the two are deeply connected. In England, Wales, and Northern Ireland, metal detecting on private land requires the written permission of the landowner. Detecting on scheduled ancient monuments – such as Hadrian’s Wall or Stonehenge – is illegal without a specific licence from Historic England or Cadw. Doing so can result in an unlimited fine and up to six months in prison.

The Portable Antiquities Scheme (PAS), administered through the British Museum, encourages the voluntary recording of archaeological objects found by members of the public. It is free to use, staffed by Finds Liaison Officers (FLOs) across England and Wales, and it represents one of the best resources available to any detectorist. Scotland operates under different legislation – the Treasure Trove system – and all finds of potential archaeological significance must be reported to the Crown via the Treasure Trove Unit in Edinburgh.

The Treasure Act 1996 is the key piece of legislation for English and Welsh finders. Under this Act, certain categories of find are legally classified as Treasure and must be reported to the local coroner within 14 days of discovery (or within 14 days of identifying the find as potential Treasure). Failure to report is a criminal offence. Treasure broadly includes:

Any coin that is at least 300 years old and made of gold or silver, provided it is found with at least one other coin
Any object that is at least 300 years old and contains at least 10% precious metal
Any prehistoric object made from a base metal alloy
Any object found in association with Treasure

This sounds technical, but in practice it means that a hoard of Roman silver denarii or a group of medieval gold coins must be reported. A single Victorian copper penny does not qualify. When in doubt, contact your local FLO – they are there to help, not to confiscate your finds.

The Moment of Discovery: What to Do on Site

Excitement is natural, but the first instinct to grab the coin and rub it clean on your jacket is the one to resist. How you handle a coin in those first few seconds can affect its condition, its identifiability, and even its legal standing if it turns out to be significant.

Follow these steps when you uncover a potential coin find in the field:

Stop digging carefully. Once you have isolated the signal, use a hand trowel or pinpointer to narrow down the location. Avoid scraping metal across metal – coins can be scratched in seconds.
Photograph the find in situ. Take at least one photo of the coin or object as it sits in the ground, before removal. Include a scale if possible – a coin or ruler placed nearby works well.
Note the exact location. Use a GPS device or your phone to record a grid reference. The what3words app is increasingly accepted for rough location recording, but an Ordnance Survey six-figure grid reference is preferable for formal records.
Place the coin in a finds bag immediately. Small resealable plastic bags, available cheaply from Regton, Serious Detecting, or any general detecting supplier, are ideal. If possible, include some of the surrounding soil – this can assist identification later.
Do not clean the coin in the field. Corrosion, soil, and patina can all provide dating information to specialists. Cleaning is a task for later, and even then, it must be done with great care.
Record the find in your field log. A simple notebook or detecting app such as Detectival or FindID is sufficient. Note the date, location, land type, depth, and any nearby finds.

Getting Home: Initial Assessment and Safe Storage

Once you are back at home, resist the urge to show your find to everyone before you have had a proper look at it yourself. Lay all your finds out on a clean surface under good lighting – a daylight lamp is a worthwhile investment for any detectorist or coin collector – and begin a basic visual assessment.

Ask yourself the following questions as you examine each coin:

What is the approximate diameter and thickness? (A ruler or digital calliper is useful here)
Is it copper, bronze, silver, or gold in appearance?
Can you see any lettering, a portrait, or a reverse design?
Does it appear to be British, Roman, or of another national origin?
Is it clearly a modern coin – post-1700, say – or does it appear older?

For storage, coins should never be kept loose in a jar or box where they can knock against one another. Even copper coins develop fresh scratches and abrasions this way, damaging what collectors call the coin’s grade or condition. Small 2×2 cardboard holders (flips), coin capsules, or foam-lined trays are inexpensive and appropriate. Lighthouse and Lindner both have UK distribution and produce quality coin storage products widely available through suppliers such as Coin & Stamp Fairs or Stanley Gibbons.

Cleaning Your Coins: Proceed With Extreme Caution

Cleaning coins is one of the most contentious subjects in the hobby, and for good reason. Improper cleaning destroys patina, removes surface detail, and can reduce the value of a coin by 90% or more. The rule most experienced collectors follow is simple: when in doubt, do not clean it.

That said, there are acceptable methods for removing loose soil and stabilising corroded coins:

Distilled water soak: Soaking a coin in distilled water for 24-72 hours will loosen soil without causing chemical damage. Change the water once or twice during the soak. This is safe for most metals.
Soft brush: A soft toothbrush or a specialist conservation brush can remove loosened material after soaking. Never use a metal implement or a stiff-bristled brush.
Olive oil (for bronze disease): Some detectorists use olive oil to treat copper and bronze coins suffering from active corrosion. This is a long-term treatment requiring months of soaking, and opinions are divided on its effectiveness.
What to avoid: Acids (including vinegar and lemon juice), electrolysis machines, Brasso, wire wool, and any abrasive compound. These methods remove material permanently.

If you have a coin that appears significant – early medieval, Roman, or of unusual size or weight – do not clean it at all. Take it to a conservator or your local FLO first. The British Museum’s Conservation and Collection Care department can offer advice, and many county museums have their own specialists.

Identifying Your Find: Resources Available in the UK

Identification is where the real interest begins. British coinage spans over two millennia, from Iron Age staters struck by Celtic tribes through Roman occupation, Saxon and Viking periods, medieval hammered issues, and the milled coinage of the modern era. Each period has its own specialists, reference books, and online communities.

Key identification resources include:

Spink’s Catalogue of British Coins: The standard reference for British coins from ancient to modern times. It is published annually and includes valuations. Available from Spink & Son in London or most major coin dealers.
The PAS Online Database (finds.org.uk): An extraordinary free resource containing over 1.7 million recorded finds from England and Wales, with photographs and identifications. Searching by coin type, period, or county can help you identify parallels for your own find.
NUMIS (the Sylloge of Coins of the British Isles): An academic but accessible series covering specific coin types in depth, particularly useful for Anglo-Saxon and Norman coins.
Online forums: The UK Detector Finds Database (UKDFD), Detecting Wales, and the forums at ukdetectornet.co.uk all have active identification threads. Members are generally knowledgeable and helpful.
Your local FLO: Finds Liaison Officers can identify most British finds and will record them on the PAS database with your permission. Their contact details are listed at finds.org.uk/contacts.

Reporting Obligations: The Portable Antiquities Scheme and Treasure Act

Recording with the PAS is voluntary for most finds but is considered best practice within the detecting community. When you record a find, it is added to a publicly accessible national database, contributing to the broader archaeological record. You retain ownership of the object, and the process is straightforward – your FLO will take photographs, measurements, and a description, and will assign the find a unique reference number.

If your find qualifies as Treasure under the 1996 Act, the process is different. You must report it to the local coroner within 14 days. The coroner will hold an inquest to determine whether the find is legally Treasure.