CoinFinderApp tests coin finder apps for metal detector users and treasure hunters who have dug a corroded or encrusted coin and need specific, coin-by-coin authentication guidance — not a generic 'check for fakes' label.
Who We Are
Three of us run CoinFinderApp: two are returning metal detector hobbyists who had shelved their gear for years, and one is a former conservation volunteer at a regional museum. We started this project because we kept running AI coin identifier apps on the corroded cents and clad quarters we were pulling from yards and fields, and the apps consistently failed to recognize them. They were trained on pristine coins. We kept asking the same question: if I clean this coin, am I destroying its value — or is it already worthless? We needed honest answers before reaching for the wire brush.
Our editorial focus is simple: apps that work only on museum-grade coins don't work for us. We test identifier apps specifically on the corroded and damaged coins that a metal detector finds in the real world, and we score them hard on whether they give you coin-specific authentication guidance that helps you decide what to do next.
Methodology
Our test set includes 28 coins dug from various sites over eighteen months: Lincoln wheat cents (early 1900s issues with deep corrosion), Indian Head cents (severely pitted), Mercury dimes (crusted with soil, partially struck), state quarters (cleaned post-recovery to remove surface soil), and Morgan dollars (showing wear and oxidation consistent with field recovery). We also test with high-resolution photographs of specimens that have been lightly stabilized but not cleaned — the state most coins are in when you first pull them from the ground.
We spend 60 to 90 hours per app over eight to twelve weeks, running each coin through the identifier multiple times under different lighting and angle conditions. We evaluate three core criteria: whether the app can recognize heavily corroded or encrusted versions of a coin it would normally identify easily; whether it provides specific diagnostic tips for authentication (e.g., 'check the rim die roll' or 'look for the mint mark on the left side of the eagle's tail') rather than generic warnings; and whether it acknowledges when a coin is too damaged for confident identification — and what you should do in that case. We re-test quarterly or after each major app update.
Our Standards
Generic counterfeit warnings don't pass our test — apps that simply say 'check for fakes' are useless when you're holding a coin crusted with seventeen years of soil. We score apps on whether they give you coin-specific diagnostics: the features that distinguish a real Indian Head cent from a fake, even under oxidation; the way a genuine Morgan dollar's reeding looks versus a smoothed imitation; the date and mint mark locations you need to verify on a corroded Lincoln. An app earns points when it tells you exactly what to look for and where. We also expect apps to surface one critical secondary insight: before you clean that dug coin to reveal details, know whether cleaning will tank its numismatic value. Most apps don't address this at all. We flag the ones that do as genuinely helpful for decision-making.
Disclosure
We do not accept paid placement from app developers; we do not review apps we have not used for at least six weeks; we do not claim expertise in ancient coins, world numismatics, or tokens beyond our test set of US circulation issues and early dollars. We do not test apps on solely pristine or museum-grade examples — any coin identifier can do that. We do not provide conservation advice or recommend cleaning methods; we only score whether an app tells you it's worth consulting a conservator before cleaning. We also do not test on counterfeits ourselves; instead, we assess whether an app gives you the real diagnostic knowledge to spot common fakes in dug-up condition.
Contact
If you've built a coin finder app and want our review, or if you've dug a coin and think we should add it to our test set, contact us via the form on this site. We also welcome field reports from metal detector users about which apps actually work when the coin is caked in soil.