Paper tax discs were scrapped in 2014, but despite them being worthless on the road, an old one could earn you a few pounds.
The discs were brought in 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.
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The old DVLA abolished paper car tax discs are now attracting the interests of enthusiastic collectors - also known as "velologists", according to the Mirror Online.
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.
Discs such as these 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.
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 sleeve 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.
