Special paint — a small amount not quite covering blubber (7)
I believe the answer is:
acrylic
'special paint' is the definition.
'a small amount not quite covering blubber' is the wordplay.
'small amount' becomes 'lick'.
'not quite' means to remove the last letter.
'covering' means one lot of letters goes inside another.
'blubber' becomes 'cry' (I've seen this before).
'a'+'lick'='alick'
'alick' with its final letter removed is 'alic'.
'alic' enclosing 'cry' is 'ACRYLIC'.
(Other definitions for acrylic that I've seen before include "Synthetic fibre or paint" , "Kind of paint" , "Textile fibre - icy Carl (anag)" , "Type of twenty Dn" , "Synthetic fabric" .)