Check pockets and purses for paper £20 and £50 notes as there are millions of them still around – and you'll soon no longer be able to use them

According to new figures published by the central bank in response to a Freedom of Information (FOI) request by BBC Wales, there are 360 million Bank of England-issued paper £20 notes (worth £7.19 billion) and 209 million paper £50 notes (worth £10.46 billion) still in circulation.

But these notes will no longer be useable from 30 September 2022. The same deadline also applies to £20 and £50 notes still in circulation that have been separately issued by various Scottish and Northern Irish banks (although AIB Group has said it will stop accepting these notes from 30 June this year). The move follows the release of new polymer versions in 2020, which were created to try to reduce counterfeiting.

Below we explain how to ensure your £20 and £50 notes don't become worthless and how, separately, to make old £10 and £20 notes and £1 coins spendable again.

How to ensure your £20 and £50 paper notes don't become worthless

To avoid your notes becoming unspendable, most of you have three options to take, regardless of where the notes have been issued in the UK, before 30 September 2022:

• Spend them.

• Deposit them into your bank account at your local bank branch or post office.

• Swap them for polymer notes at your bank.

If you're unsure what you're looking for, check out pictures of the soon-to-be-withdrawn Bank of England paper £20 and £50 notes on its website.

If you miss the deadline, or have other withdrawn Bank of England notes or old UK £1 coins floating about – here's how to make them spendable again

The same FOI data revealed there were 113 million Bank of England-issued £5 notes (worth £566 million) and 73 million paper £10 notes (worth £726 million) still in circulation, despite these being withdrawn in 2017 and 2018 respectively.

According to new figures from the Royal Mint, there are also £105 million old round £1 coins still in circulation. These lost their so-called "legal tender" status in October 2017.

If you're unsure what you're looking for, check out pictures of the old 'round pound' on the Royal Mint website and view images of the old paper £5 and £10 notes on the Bank of England website. If you find any, here's what to do with them:

• Your bank may swap or deposit old paper notes and coins. Banks don't legally have to accept old paper notes and coins once they've been withdrawn from circulation. However, some may continue to allow you to swap them, while others may let you deposit old notes and coins into your account.

  Of the other major banks that came back to us, Barclays, Halifax, Lloyds, Nationwide, NatWest and Santander all said you can deposit old coins and notes into your account. We also asked PayPoint, which allows Monzo customers to deposit cash into their account. These customers will have to go to the Bank of England to swap old notes should they have them after the deadline.

• The Post Office will deposit old paper notes and coins into your bank account, which you can then withdraw. To do this, your bank will need to be signed up to receive cash deposits via the Post Office. You can check this on the Post Office website, although many major providers are signed up. You can't, however, do a direct cash swap at a post office.

• For notes only: If your bank or post office can't help, you can swap paper notes for polymer versions at the Bank of England. You can do this in person at the Bank of England counter at Threadneedle Street, London. You may need to provide two original identity (ID) documents (one photo ID and one proof of address) for any exchange – this is also mandatory for any exchange of £700 or more. To check what ID the Bank of England accepts, see the 'Identification we accept' page on its website.

  You can also do this by post, which may be the only option for those who don't live or work in London – though if you do this, consider paying extra for a delivery service that provides compensation if your post goes missing. You can find out more on the Bank of England website. Neither the Bank of England or the Royal Mint will accept old coins.

• Alternatively, ask a friend to help. If your bank or post office won't accept your old notes and coins, and you can't get to the Bank or England or you're worried about sending cash in the post – see if a friend or family member can ask their bank or post office instead. They can then transfer or hand over the money to you.

What to do with Scottish-issued £20 and £50 notes if you miss the deadline

Scottish paper £20 and £50 notes, which were issued by Bank of Scotland, Clydesdale Bank and Royal Bank of Scotland, will be replaced by polymer ones from 30 September 2022.

It will be at the discretion of retailers and service providers as to whether to accept them after this, but they don't have to. So here's what to do with these old notes:

• Your bank may swap or deposit old paper notes. Bank of Scotland and Royal Bank of Scotland will accept deposits from their customers of old paper notes issued by any Scottish bank, while Bank of Scotland will also exchange them. Clydesdale Bank will exchange all Scottish-issued notes for their own customers, while it added that it would allow non-customers to swap up to £250.

• The Post Office will deposit old Scottish paper notes into your bank account, which you can then withdraw. To do this, your bank will need to be signed up to receive cash deposits via the Post Office. You can check this on the Post Office website, although many major providers are signed up. You can't, however, do a direct cash swap at a post office. The Post Office told us this is a service it provides out of choice across all of its branches, but it's not something it has to do.

How to swap Northern Irish-issued £20 and £50 notes once they're pulled

Northern Irish paper £20 and £50 notes, which were issued by Bank of Ireland, Northern Bank Limited (which trades as Danske Bank) and NatWest Bank (which trades as Ulster Bank), will be replaced by polymer ones from 30 September 2022. But AIB Group (previously trading as First Trust Bank) will withdraw its current paper £20 and £50 notes from 30 June 2022 – it said it is doing this as a response to the increase in online banking.

Again, it's at the discretion of retailers and service providers as to whether to accept notes after these deadlines, but they don't have to. So here's what to do with them:

• Your bank may swap or deposit old paper notes. AIB Group, Bank of Ireland, Northern Bank Limited and Ulster Bank will exchange and deposit notes issued by any Northern Irish bank. Ulster Bank has said that its own customers can exchange paper banknotes with no monetary limit, while non-customers can swap notes up to £250 in total. We've asked NatWest Bank for its position and we'll update this story when we know more.

• The Post Office will deposit old Northern Irish paper notes into your bank account, which you can then withdraw. To do this, your bank will need to be signed up to receive cash deposits via the Post Office. You can check this on the Post Office website, although many major providers are signed up. You can't, however, do a direct cash swap at a post office. The Post Office told us this is a service it provides out of choice across all of its branches, but it's not something it has to do.