Could you make money from your old paper £10 notes?
The new plastic £10 notes go into circulation tomorrow, and the old paper versions will gradually be phased out between now and spring next year.
And, as with the recently-introduced polymer £5 notes, it's time to start checking piggy-banks and coat pockets to make sure you get rid of the old tenners in time.
But before you spend them, it may be worth taking a good look at each note, as some could be worth more than their face value.
According to banknote expert Andrew Pattison of auction house Spink & Son, you're most likely to turn a profit on notes printed in the first batch, with a serial number beginning with LH01.
They'll need to be in really good condition, though.
"Mint state notes are worth many times more than one with even the slightest fold or blemish," he tells the Sun.
"In fact, for modern material like this, notes that are not mint state are generally just face value."
In fact, an uncirculated paper £10 note is up for sale on eBay, with a current top bid of £13.50.
Also valuable, says Pattison, will be notes from the last print run. We don't yet know what the serial numbers will be, but he suggests it's likely to be ME40 or thereabouts.
There may also be a chance that you can sell a note for more than its face value if it has an unusual combination of numbers, or if you have several notes with consecutive serial numbers - but don't expect to make big bucks.
There are currently around 723 million old paper £10 notes in circulation. In the past, as old notes were withdrawn, they were burned and used to heat the Bank of England.
More recently, though, the bank has started recycling them for compost, which is then used for farming.
So while money may not grow on trees, your vegetables may be growing on money.