24 across
Track
down
a
very
tiny
amount
(5)
Track down a very tiny amount (5)
hints
0
checks
0
hints
The whole clue is the definition (& lit or double definition).
How the clue works
Two definitions for the price of one here. Track down gives you TRACE, and a very tiny amount is also a TRACE — both halves of the clue pointing independently to the same answer.