Container found back among the Pompeian ruins (3)
I believe the answer is:
urn
'container' is the definition.
(I know that Urn is a type of container)
'back among the pompeian ruins' is the wordplay.
'back' says the letters should be written in reverse.
'among' says the answer is hidden in the clue.
'nru' is hidden within 'pompeian ruins'.
'nru' written backwards gives 'URN'.
'found' acts as a link.
(Other definitions for urn that I've seen before include "Pot for human ashes" , "Funereal vase" , "Tall stemmed vase" , "Source of tea" , "Run to get large vase" .)