Go on working metal in cruset, regularly (8)
I believe the answer is:
continue
'go on' is the definition.
(synonyms)
'working metal in cruset regularly' is the wordplay.
'working' becomes 'on' (e.g. a machine is working or on).
'metal' becomes 'tin' (tin is a kind of metal).
'in' means one lot of letters goes inside another.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The alternating letters of 'cruset' are 'cue'.
'on'+'tin'='ontin'
'ontin' put into 'cue' is 'CONTINUE'.
(Other definitions for continue that I've seen before include "Proceed" , "Last" , "Persist" , "Carry on" , "Don't stop, keep going" .)