A taxi driver had his licence temporarily suspended after using a Costa coffee cup lid as a fuel cap.
The vehicle was stopped in January as Sandwell Council, West Midlands Police and the Driver and Vehicle Standards Agency (DVSA) were carrying out safety checks.
The council said diesel was seeping through coffee cup lid and was causing a danger to other motorists - especially motorcyclists.
The driver's Hackney Carriage licence was suspended for 24 weeks on Tuesday after other defects were found - such as a faulty headlight and tyres being close to the legal limit.
The DVSA inspector who carried out the checks said: "The clear conscious decision to fit a Costa coffee cup lid to the fuel filler neck was inexcusable."
He added that he was "shocked at the level of non-compliance and the blatant disregard to road safety".
Sandwell Council's cabinet member for public health and protection, councillor Elaine Costigan, said: "This was a really serious and potentially very dangerous thing to do.
"Generally we see very good standards of vehicle maintenance when we make these checks - it's rare to see something quite this irresponsible."
Additional reporting by Press Association.