A fashion student has been warned not to sell prohibited items on the clothes app, Depop, after she posted an advert for a top made from a train seat cover.
Mhari Thurston-Tyler made the bandeau out of a Chiltern Railways seat cover designed to promote social distancing during the coronavirus pandemic.
The 20-year-old sold the top for £15 but later refunded her customer and took the advert down.
Depop said the item "clearly violates our terms of service".
The app for buying and selling second-hand clothes said the sale of stolen goods was banned - but Ms Thurston-Tyler denied stealing.
She told BBC News she found two of the blue seat covers "balled up on the floor" outside Marylebone station in London in September.
Ms Thurston-Tyler, who is a fashion student at Central Saint Martins, re-sewed one of the covers to make it fit her, before deciding to advertise the second cover on Depop.
"I have no money at the moment so decided to put the second one on Depop to see if anyone would buy it," she said, adding that the app had become her main source of income as she has struggled to find other work during the pandemic.
"I have to resort to little things like this to make ends meet, to pay the bills."
In the advert, Ms Thurston-Tyler models the seat cover and describes it as a "social distancing crop", adding: "Got a few of these can do different sizes."
Ms Thurston-Tyler, from Kenilworth in Warwickshire, said a Depop customer paid her £15 and ordered a crop top "in extra small".
But realising she should not be making money out of Chiltern Railways' property, Ms Thurston-Tyler refunded the customer 15 minutes later and took the advert down shortly afterwards.
"I didn't steal it but I understand it's not right to re-sell it," she said.
A Depop spokesperson said Ms Thurston-Tyler would be banned from the platform if she listed any other prohibited goods.
"We explicitly prohibit the sale of illegal and unlawful content on the app, including any stolen goods," they said.
"This item clearly violates our terms of service, but as it has been removed by the seller and is no longer for sale on the platform, we will not be taking immediate steps to ban this user."
Ms Thurston-Tyler said she hopes to make her own line of crop tops with the words "children railways" on the design, while "the hype" of the viral moment continues.
Chiltern Railways said it has been using the social distancing "seat sashes" since the beginning of the UK's Covid epidemic.
A spokeswoman added: "Whilst we appreciate this new take on railway memorabilia, these items are there to help customers travel with confidence and we would respectfully ask that they are left in place."