Police officers in Sheffield want to trace the owner of a haul of metal found in a van.
Officers found the metal after stopping a van over an unrelated matter in Holbrook Avenue, Holbrook, Sheffield, in the early hours of Saturday.
A 19-year-old man driving the van was interviewed under caution over the metal.
A South Yorkshire Police spokeswoman said: "Police are now looking to trace the owner of the metal and would like to hear from anyone who was information as to who it could belong to. "The metal cylinders have Micron Filter Unit 2 written on in yellow.
"Do you know who the metal belongs to?"
Anyone with information should call South Yorkshire Police on 101.