help and explanations please-across clues have one letter removed whenever it occurs in answer-number in brackets= untreated clue
13a money off coffee?left one,being indifferent (11) ??????C? remove n
15a dissolute fellow to smear extortionist (9) ??K?????remove c
27a quivers fell,head of arrow put back (10) remove p-possibly ends in s
1d ineral water ahead's taken with fermented raisin 11 A????S??????
nb down clueshave letter added before entry-add s
thanks