8 across
Use
unknown
technique
for
out-of-this-world
23
(5,3)
Use unknown technique for out-of-this-world 23 (5,3)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
out-of-this-world 23 is the definition — 23 down is candy, and Milky Way is a candy that's literally out of this world. The wordplay is a charade: MILK (to use, in the sense of exploit) plus Y (the mathematical unknown) plus WAY (technique).