Paper tax discs may have been scrapped years ago - but drivers who hung onto an old one could now be able to sell it for hundreds of pounds.
These tax discs were brought in 100 years ago in 1921, and became commonplace in all car windscreens.
Motorists would display them on the inside front of their windscreen to prove vehicle tax - or vehicle excise duty - had been paid .
But since October 2014 paper tax discs were phased out in favour of an electronic register.
Around 1.7billion tax discs were issued during this 100-year period, with most being destroyed.
But some of the ones still surviving can sell for hundreds of pounds online, according to LeaseCar.uk.
On eBay the discs are being sold for up to £1,250.
The pricey tax disc in question dates back to 1970, and is unused and pre-decimalisation.
These rare quirks made it more valuable to collectors, known as 'velologists' .
For example, in August 2014, the DVLA ran out of perforated paper - the special material used to print tax discs on.
It meant for the next two months, until they ceased production entirely, people would receive non-perforated tax discs, which they'd have to cut out themselves.
Today, these 'limited edition' discs are considered rare and experts reckon they'll accrue the most in value in the long term..
Likewise, those with typos and printing errors are also seen as more valuable.
Obviously, those in good condition are worth more than tatty or torn tax discs.
And if your tax disc dates back to the Second World War, it could also sell for more.
Vehicles used for the war effort had tax discs with 'War Service' marked on them, and are rare.
Regardless of the year, tax discs which have their sleevage intact (the paper that surrounds the disc) are also more collectable.
But if you don't have such a rare tax disc, don't lose heart.
Even fairly average tax discs from as recently as 2009 are trading for up to £300 on eBay.
A LeaseCar.uk spokesperson said: "Many people find it fascinating to explore buying and selling websites to look at the variety of used car tax discs that are available today.
“These small round pieces of paper are an important part of our motoring heritage and it is particularly poignant that on the 100th anniversary of their introduction on our roads that car tax discs from as early as the 1920s are actively available to buy.”
Vehicle tax was brought in with the 1888 Budget. A tax system especially for cars came in in the Roads Act 1920.
