Old round pound coins will cease to be legal tender next week - but some shops will still be accepting them after the deadline.
People have been urged to rummage through their wallets, coat pockets and sofas so that they can spend them, bank them or give them to charity before this date.
Over the past six months, more than 1.2 billion round pound coins have been returned but some £500 million worth of the old coins are still in circulation.
They were replaced by the new 12-sided pound coin in March. It resembles the old threepenny bit and boasts new high-tech security features to thwart counterfeiters.
The round pound coin was first produced by the Royal Mint in April 1983 to replace £1 notes.
So when will we have to stop using old pound coins?
From midnight on Sunday October 15, the round pound will lose its legal tender status.
This means stores cannot hand out old pound coins as change and can refuse to accept them as payment.
Where will we still be able to spend the old pound coins?
Discount retailer Poundland has said it will "ignore" the Royal Mint's deadline and continue to accept old £1 coins in more than 850 of its stores across the country until October 31.
And Britain's biggest supermarket Tesco told ITV News: “We’ve been updating our systems ready for the new pound coins, but to help customers who still have the old coins, we’ll continue to accept round pounds at our tills and self-service machines for an additional week.”
A trade association representing small shops has advised its members to continue accepting the round coins to provide a "useful community service" to customers.
The Federation of Small Businesses said: "It would help if small firms knew they were allowed a short transition period to collect the old coins if they wish to and are willing to bank them, but not give out to customers."
What about banks, are they still accepting the old pound coins?
Major banks have said that while they encourage customers to allow enough time to hand in their old coins, they will continue to accept deposits of round pounds from their customers after October 15.
Barclays said its own customers can continue to deposit their old round pounds into their accounts, but added: "We would recommend that customers allow sufficient time to return old coins rather than leave it until legal tender status is withdrawn."
RBS/NatWest, Santander, Nationwide Building Society and Lloyds Banking Group, which includes Halifax, also said they will continue to accept round pounds as deposits from their own customers after they cease to be legal tender.
RBS/NatWest also said it would encourage customers to try to hand in their old coins as soon as possible.
And the Post Office?
People may also find they can still hand in the old £1 coins at the Post Office after this date.
The Post Office said customers can continue to deposit their old round pounds into any of their usual high street bank accounts through any post office - even after October 15 - "until further notice".
What has the Government said?
A spokesman for the Treasury said: "Businesses told us they wanted certainty on a cut-off date, which is why we introduced the October 15 deadline.
“We have worked tirelessly with businesses for several years to support their preparations for this, including launching a campaign a year ago to help firms educate their workers.
“The overwhelming majority of businesses tell us they are ready, and the small minority who choose to keep accepting the old coin, after it ceases to be legal tender, will have to make their own arrangements with their banks.”