Glue, for example, in black (7)
I believe the answer is:
solvent
This clue is a double definition.
'glue for example' is the first definition.
(glue is a solvent)
'in black' is the second definition.
(in the black means financially solvent)
(Other definitions for solvent that I've seen before include "not on the rocks" , "afloat" , "Creditworthy" , "Financially sound" , "In credit" .)