Cleaner drinks tea with second customer (9)
I believe the answer is:
purchaser
'customer' is the definition.
(I know that purchaser is a type of customer)
'cleaner drinks tea with second' is the wordplay.
'cleaner' becomes 'purer' ('pure' can be similar in meaning to 'clean').
'drinks' indicates putting letters inside.
'tea' becomes 'cha' (cha is a type of tea).
'with' is a charade indicator (letters next to each other).
'second' becomes 's' (common abbreviation).
'cha'+'s'='chas'
'purer' going around 'chas' is 'PURCHASER'.
(Other definitions for purchaser that I've seen before include "Shopper" , "I'll buy" , "Buyer" , "Punter" , "customer" .)