Britons have just 100 days to spend all their old £20 and £50 paper notes.
After 30 September 2022, the paper banknotes will no longer be legal tender.
"So we are encouraging anyone who still has these to use them or deposit them at their bank or a Post Office during these last 100 days,” the Bank of England announced in a statement.
Although most of the paper banknotes have been replaced with new polymer versions, there are still £14bn worth of paper notes in circulation - 300 million £20 banknotes and 160 million £50 notes.
“Changing our banknotes from paper to polymer over recent years has been an important development, because it makes them more difficult to counterfeit, and means they are more durable,” said the Bank of England’s chief cashier Sarah John.
“The majority of paper banknotes have now been taken out of circulation, but a significant number remain in the economy, so we’re asking you to check if you have any at home. For the next 100 days, these can still be used or deposited at your bank in the normal way.”
All old paper banknotes can be exchanged by the Bank of England at any time.