I'm a coin expert - the five most valuable Olympic 50ps in your change worth up to 30 times face value

A COIN expert has revealed the five most valuable Olympic 50ps – and one could sell for up to 30 times its face value.

Rare coins and bank notes can fetch for hundreds and sometimes thousands of pounds.

So it's well worth digging around your spare change to see if you've got any hiding away.

Some 50ps have sold for over £200 and an "error" 2p went for hundreds of pounds.

But some rare coins come as part of a set, and have been known to sell for multiple times their face value.

Almost 30 rare 50p pieces were put into circulation in 2011 to commemorate the 2012 London Olympics.

How to spot a rare coin

Rare coins come in all shapes and sizes and what defines them as rare varies from piece-to-piece.

In most cases, a coin is considered rare if it has a low mintage figure – this is how many are created and put into general circulation.

For example, if a coin has a mintage figure of 1,000,000 and another has a figure of 1,100,000, the higher figure is the least rare.

Generally, the rarer a coin is the more you are likely to get for it when it comes to selling, although this isn't always the case.

You can find out a coin's mintage figure by going on The Royal Mint's website.

Some other coins are considered rare if a manufacturing error occurred when they were made.

But there's usually a lot less of these types of pieces in general circulation. They can be worth a small fortune though.

When it comes to actually selling a rare piece, you have three options – Facebook, eBay or auction.

If you're selling through Facebook, be wary of the risks.

Fraudsters have contacted sellers in the past saying they want to buy a rare coin and ask for money up front for a courier to collect it.

But the items are never picked up, leaving sellers out of pocket.

To stop this happening, it's worth meeting the buyer in person and in a public meeting spot that's well-lit.

If you're selling through eBay, you'll have to start by registering for an account and then listing a product.

Make sure you've got good pictures and mention the condition of the coin to avoid leaving buyers disappointed.

Bear in mind though, the safest way to sell a rare coin will more than likely be through auction.

You can organise doing this via The Royal Mint's Collectors Service, which has a team of experts who can authenticate and value a coin.