B ritual people have been encouraged to check couches and piggy banks when 145m old coin coins have still not been returned to Royal Mint.
It is feared that many of these coins, which were discontinued in October 2017, may be lost. Only 24 million so far have been returned, which is a fraction of the outstanding money.
There were around 1.7 billion round 1 coins in circulation at the start of the six-month transition period in March 2017.
The Royal Mint has reassured those who hold onto their coins that they can still get repaid if They deliver them to their nearest bank.
Coins returned to banks and stores have been melted down to make the new £ 1
An official Royal Mint said, "Our communication campaign encouraged the return of old £ 1 coins when legal tender was removed.  "The small percentage of coins that are not returned can continue to be deposited on a customer's account at the highest street banks in the UK. "
They added," We expect some returns for years to come when people find these coins. "
The new coin was designed to be much harder to fake, with new features that include a hologram image on the coin that changes from a £ symbol to the number 1 in different angles, micro-letters on the side of the coin, made from two metals and a "hidden high security feature" that Royal Mint has refused to disclose.