Rubbish or bin set outside M&S at one time (9)
I believe the answer is:
brimstone
'rubbish or bin set outside' is the definition.
I can't tell whether this defines the answer.
'ms at one time' is the wordplay.
'ms' becomes 'brims' (I can't explain this - if you can you should give a lot more credence to this answer).
'at' means one lot of letters go next to another.
'time' becomes 't' (abbreviation).
'one' put after 't' is 'tone'.
'brims'+'tone'='BRIMSTONE'
Can you help me to learn more?
(Other definitions for brimstone that I've seen before include "hellish punishment" , "Sulphur (when associated with hellfire)" , "Old name for sulphur" , "Insect" , "Yellow butterfly" .)