Rubbish book seen in service station (7)
I believe the answer is:
garbage
'rubbish' is the definition.
(both can mean refuse or trash)
'book seen in service station' is the wordplay.
'book' becomes 'b' (abbreviation for book).
'seen in' means one lot of letters goes inside another.
'service station' becomes 'garage' (I can't explain this - if you can you should believe this answer much more).
'b' inserted into 'garage' is 'GARBAGE'.
Can you help me to learn more?
(Other definitions for garbage that I've seen before include "Refuse - worthless talk" , "Brag about age? - that's rubbish" , "'Refuse, rubbish (7)'" , "Rubbish - invalid computer data" , "Worthless matter" .)