“Nothing beats finding gold,” David Villanueva tells me as we drive towards the “site” – a field in rural Kent, not far from Canterbury — where, armed with metal detectors, we will be hunting for treasure.

Mr Villanueva is confident that the machines will turn up something of interest. The land – situated between medieval villages – has already produced Roman, Tudor and Georgian artefacts, including a silver Elizabeth I coin.

Mr Villanueva, 55, is one of the country’s 8,000 or so dedicated “detectorists”. Once reviled by archaeologists as looters bent on plundering heritage for profit, they have enjoyed a radical change of image in recent years and now work closely with museums and excavators. Many map their finds meticulously and report thousands of artefacts — 57,566 last year — to the British Museum’s Portable Antiquities Scheme (PAS). In January David Lammy, the Culture Minister, called them “the unsung heroes of the UK’s heritage”.

An initial lust for gold inspires most to take up the hobby. But Clive Sinclair, of the National Council for Metal Detecting, says that thousands of detectors end up in cupboards when their owners’ dreams of booty come to nothing despite hours of legwork. Roger Bland, head of the PAS, which allows archaeologists to interpret the distribution and significance of finds, says that artefacts such as Roman coins fetch as little as a pound or two each on eBay.

Mr Sinclair says that the hard core of detectorists who weather any initial disappointment tend to develop an intense interest in local history and archaeology, often aided by Channel 4’s Time Team, which allows them to see the historical significance and real value of battered objects that are worth nothing in hard cash. Many keep all their finds, building vast collections spanning millennia.

The only finds that Mr Villanueva has sold have been compulsorily purchased under the Treasure Act. The legislation rules that anyone who finds a group of coins buried together, or any artefact that is 300 or more years old and has a 10 per cent gold or silver content, must declare it to the coroner within 14 days. The finds are examined by museum curators, who can choose to buy them at market value. About half of the 500 or so finds reported each year are purchased in this way.

Mr Villanueva’s seven treasure finds – from 35 years in the hobby, with five-hour detecting trips twice a week since 2005 – include a cache of nine Iron Age gold coins bought by the Canterbury Museum for between £180 and £220 each, a late medieval gold ring and Roman, Saxon and medieval jewellery. Half of each payout has gone to the landowner in a standard preagreed 50-50 split. The 15th-century ring is his favourite find and raised £3,750.

My haul after a couple of hours is more modest. A run of shotgun cartridge caps is followed by a battered Stella Artois can, c 2006, and a copper button worn beyond recognition. “Probably military, 20th century,” Mr Villanueva says. Next comes a lead weight for spinning wool, a “spindle whorl”. Then a 1916 penny, followed by a lead pistol ball and a worn George II halfpenny, dated 1740.

In the same short space of time, Mr Villanueva has found a couple of bronze halfpennies (18th and 20th century), another pistol ball, two buttons and assorted items of “horse furniture” – plain harness fittings that can be difficult to date.

He says that such finds, with negligible sterling value, can reveal significant aspects of our social history. My spindle whorl, for instance, speaks of a time when spinning wool into thread was a vital cottage industry.

Back in town I take my finds for more detailed identification at the British Museum.

Sally Worrell, a finds adviser, says that my spindle whorl is probably medieval, though precise dating is impossible. She says that my pistol ball’s diameter, or bore, dates it to the 17th or 18th century and it may have been fired in a Civil War skirmish. Of unexpected interest is a piece of flint I picked up on the off-chance. Ms Worrell says that one edge was worked into a scraper in the Bronze Age and could have been used to strip hides or clean leather. According to Coincraft, an established dealer, none of these items – or my coins – has any commercial value.

A decent “switch-on-and-go” metal detector costs between £200 and £700. For that outlay – and thousands of hours of site research and legwork — a steady stream of collectibles can be yours. The chances are that some of these finds will have a cash value, a handful perhaps in the hundreds or even thousands of pounds.

Beginners’ guide for budding ‘detectorists’

Join a club: The National Council for Metal Detecting (NCMD) has contact details for clubs that offer group events and an opportunity to pool knowledge and experience. Members can advise on the best detectors and other kit to buy. Go to www.ncmd.org.uk.

Do your research: Sites close to historic settlements or routes are most likely to yield coins and other artefacts. Old maps, estate records and books on local history can help to identify hotspots. It is worth checking the county archives, at www.nationalarchives.gov. uk/archon.

Obtain the landowner’s permission: Always ask for permission to search a site. David Villanueva suggests writing a letter outlining your site research and why detecting could be productive. Establish how any treasure finds will be split and put that agreement in writing, with signatures.

Record your finds: The Portable Antiquities Scheme (PAS) maps and catalogues finds across England and Wales dating up to about 1650, allowing archaeologists to interpret their distribution. Go to www.finds.org.uk.

Report treasure: If your find could qualify as “treasure” — coins buried together, or anything 300 or more years old containing gold or silver — report it. If the find is compulsorily purchased, you will be awarded its full market value, based on assessments by leading dealers. Contact the PAS if in doubt.

Codes of conduct: The PAS and NCMD websites give detailed guidelines on responsible metal detecting.

Top finds in the British Museum

The Hoxne Hoard: Eric Lawes, a retired gardener, received a half-share of a £1.75 million payout for 15,000 gold and silver Roman coins, plus jewellery and tableware, found in Suffolk in 1992. The hoard is thought to date from the turbulent time of the Roman withdrawal from Britain in the early 5th century.

The Winchester Hoard: In 2000 Kevan Halls found more than a kilogram of intricate Iron Age gold jewellery, made in Rome for a British chieftain, scattered across a field near Winchester, Hampshire. He shared £350,000 with the landowner.

The Ringlemere Cup: This Bronze Age gold cup, dated to about 1600BC was found by Cliff Bradshaw in Kent in 2001. The museum paid £270,000 for the plough-damaged artefact.

Yet to find: King John lost his entire treasury in 1216, when his baggage train took an ill-advised shortcut across the tidal marches of the Wash in East Anglia.