Hurry to obtain caustic extract from newspaper (5,7)
I believe the answer is:
press cutting
'extract from newspaper' is the definition.
'hurry to obtain caustic' is the wordplay.
'hurry' becomes 'press'.
'to obtain' means one lot of letters go next to another.
'caustic' becomes 'cutting' (I've seen this before).
'press'+'cutting'='PRESS-CUTTING'
(Other definitions for press cutting that I've seen before include "Item snipped from newspaper" , "newspaper article" .)