Next time you're given a handful of change in a shop, stop and look before chucking it back in your purse or throwing it into a jar at home.
Earlier this year, a 2p coin sold for almost £1,400 at auction because it was silver instead of copper.
While you'll need to be very lucky indeed to find a silver 2p piece, there are other more common coins that could be worth more than you think.
Here's a guide to the valuable coins that can turn up in your change . . .
Rare find:Earlier this year, a 2p coin sold for almost £1,400 at auction because it was silver instead of copper
Kew Gardens 50p — value £30-£50
In 2009, around 210,000 50p coins were issued with a picture of the iconic Kew Gardens Pagoda.
With a total of 950 million 50p coins currently in circulation, the Kew Pagoda coins can be incredibly hard to spot
While this might sound like a lot, usually when a new 50p is printed more than five million are struck.
And with a total of 950 million 50p coins currently in circulation, the Kew Pagoda coins can be incredibly hard to spot.
If you get your hands on one, numismatists — or currency collectors — are typically willing to pay around £30-50 on online marketplace eBay.
Undated royal 20p — value £100
In 2008, the Royal Mint launched a Royal Shield of Arms series of coins.
A different detail from the shield was printed on the reverse (tails) of 1p, 2p, 5p, 10p, 20p and 50p coins. Placed together, they reveal the complete shield.
But a mistake means an unknown number of the 136 million 20p coins printed between 2008 and 2009 do not have the date stamped on them.
Normally, a 20p coin will have the year it was minted stamped on either the heads or the tails side of the coin.
But if you find a 20p with no date, they are heralded by experts as the 'Holy Grail of change collecting'.
Buyers are willing to pay more than £100 for one, says Gerry Buddle of the London Numismatic Club.
This undated 20p coin from 2008, part of a Royal Shield of Arms series of coins, is worth around £100
Silver 10p-sized 2p — value £1,400
These are created when a blank 10p coin accidentally finds its way into the 2p mint.
Only two instances of this happening have been recorded in recent years, with the Royal Mint unable to confirm the likelihood of one being found again.
Their rarity means they are worth a great deal to collectors.
In May, a 2015 dated silver 2p coin was dropped into a Royal British Legion collection tin in Wiltshire and later sold at an auction for nearly £1,400.
The coin had the dimensions of a regular 10p and was silver, but had the 2p Royal Shield of Arms stamped on it.
In 2014, a silver 2p coin dated 1988 sold for more than £1,350.
New pence 2p — value £500
An error in 1983 means there are a small number of 2p coins from that year which say 'new pence' rather than 'two pence'
All 2p coins minted before 1982 should say 'new pence'. Those minted after this date should say 'two pence'.
But an error in 1983 means there are a small number of 2p coins from that year which say 'new pence'.
Royal Mint does not know how many exist but today they can fetch more than £500 — though only if it is dated 1983.
Commonwealth £2 — value £20
The Northern Ireland 2002 Commonwealth Games £2 is considered the rarest £2 coin, and could be worth up to £20
The Northern Ireland 2002 Commonwealth Games £2 is considered the rarest £2 coin. There were just 485,500 minted.
With a total of 417 million £2 coins in circulation, they are not easy to come by and typically sell online for around £20.
Peter Rabbit 50p — value £20
This Peter Rabbit 50p could be worth 40 times its face value
These coins were released at Easter this year.
The Royal Mint won't reveal exactly how many it made, but it only put them at the tills of four attractions and National Trust properties.
It is the first time a fictional character has been printed on a coin and they are fast disappearing from circulation because collectors are hoarding them.
Some are already selling online for £20, according to website Change Checker — 40 times the coins' face value.
The Euro 50p coin — value £50
The rarest 50p coin is the 1992-93 EC Single Market design. The coin illustrates a table with 12 stars representing the capital city of each member nation at the time.
There were just 109,000 made and they can fetch around £50 online.
Experts say their value is likely to increase further following Britain's decision to leave the EU.
However, it won't turn up in your change without you realising as they are no longer used. They are one of the chunkier 50p coins replaced by the slimmer model in 1997.
Red herrings to watch out for…
Since 1997 many people have snapped up a £2 coin with a portrait of the Queen wearing a necklace, believing it to be rare.
But a huge 14 million of these coins were struck, so it's not likely to be worth any more than £2.
In June, Money Mail reported how sneaky eBay sellers are trying to trick coin enthusiasts into paying thousands of pounds for a Benjamin Britten 50p piece.
Sellers claim the coins are hard to come by. But 5.3 million have been printed since 2013, so they are unlikely to be worth more than their face value of 50p.
Not all coins that look unusual will be worth anything extra — even including being the wrong colour.
Yasmin Britton, of Change Checker, says: 'It could be that the coin is a mis-strike so the stamp is not central or complete. This can happen when a tiny bit of dirt gets into the machine and does not mean a coin is rare or valuable.
'People may have plated their coins for various reasons and it's even possible the coin is a fake.'
There are some coins that were once relatively common but are no longer in circulation.
You’re unlikely to come across them if you are not a collector but it’s possible you have one that’s been handed down through the family.
For example, a shilling with a portrait of William and Mary from the 17th century printed on it can fetch more than £1,000 if it’s in extremely good condition.
But condition is critical. There are many examples on eBay that are not in the condition required to be a good investment.
Victorian shillings, no matter what the year, in good condition can sell for £70.
Rarer coins fetch even larger sums.
In 2006, a gold coin of Edward III dated from 1343-4 sold for a whopping £460,000.
The Edward III double florin, known as a double leopard and with a face value of six shillings, was circulated from December 1343 until July 1344.
Mr Buddle adds: ‘This coin is rare because when issued it got the value of gold relative to silver wrong, so was rapidly withdrawn and replaced by the noble, which is much more common - though you would still have to pay about £2,000 for one of those.’
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The Royal Mint Museum offers a service where you can get rare coins checked by an expert for free, but this is not a valuation service. Call 01443 623 004 or go to royalmintmuseum.org.uk.
The Royal Mint says those looking forvaluations should visit the British Numismatic Trade Association website which has a list of reputable coin dealers in who can value coins.
Stanley Gibbons also offers a free valuation service through its rare coin division, Baldwin's for those looking to auction or sell the item.
If the coin is particularly rare, you may have to pay to carry out extra research.
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The 2p coin from 1983
The rarest copper coins in circulation are reported to be from a batch of 2p coins that were minted in 1983 and feature a mistake. These coins feature the wording “new pence” on their fronts when they should have said “two pence”.
A rare two pence coin has sold for more than £1,000 due to an error during the minting process. Produced between 1971 and 1981, the coins features the words "new pence" which was used on all of the 2p pieces until "two pence" was introduced in 1982.Are the 2p new pence worth anything? ›
YOU could have 2p coins in your change that are worth a lot more than their face value. Here's a look at the rarest 2p coins currently in circulation, worth as much as £900. Hundreds of millions of two pence pieces are minted every year, so the vast majority are only worth their face value.What is the most valuable 50p coin? ›
The Royal Mint has revealed the most valuable 50p coin, ahead of the 1971 decimalisation's golden anniversary. The rarest is the Kew's Garden 50p, which was designed to mark the 250th anniversary of the gardens in 2009. Only 210,000 coins were ever minted with this design.