Shop soiled? Not so, the reverse (4)
I believe the answer is:
deli
'shop' is the definition.
(I've seen this before)
'soiled? not so the reverse' is the wordplay.
'not' indicates named letters should be taken away.
'the reverse' says the letters should be written backwards.
'soiled' with 'so' taken away is 'iled'.
'iled' reversed gives 'DELI'.
(Other definitions for deli that I've seen before include "Food shop (colloq.)" , "Fine-food store" , "Exotic food shop" , "part of supermarket" , "place to buy food" .)