Crib clue about melting-pot (8)
I believe the answer is:
crucible
'melting-pot' is the definition.
(I've seen this before)
'crib clue about' is the wordplay.
'about' indicates an anagram.
'crib'+'clue'='cribclue'
'cribclue' anagrammed gives 'CRUCIBLE'.
(Other definitions for crucible that I've seen before include "Vessel for molten metal" , "Metal-melting container" , "smelting vessel" , "hearth" , "Pot in which metals are melted" .)