Barrel containing last of methylated spirit (4)
I believe the answer is:
drum
'barrel' is the definition.
(I know that barrel can be written as drum)
'last of methylated spirit' is the wordplay.
'last of' suggests the final letters.
'spirit' becomes 'rum' (alcoholic spirit).
The last letter of 'methylated' is 'd'.
'd'+'rum'='DRUM'
'containing' is the link.
(Other definitions for drum that I've seen before include "Tap" , "Thing to be beaten - but not as a container!" , "- Taps (Walt Whitman)" , "beat" , "12th" .)