Container for chow mein has small stone in it (4,3)
I believe the answer is:
mess tin
'container for chow' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'mein has small stone in it' is the wordplay.
'has' is an insertion indicator.
'small' becomes 's' (abbreviation - e.g. clothes size).
'stone' becomes 'st'.
'in it' is an insertion indicator.
'mein' enclosing 's' is 'mesin'.
'mesin' going around 'st' is 'MESS-TIN'.
Can you help me to learn more?
(Other definitions for mess tin that I've seen before include "where Tommy Tucker was seen" , "Soldier's food dish" , "Camping item" .)