Cleaner cup possibly leads to excessive drinking (10)
I believe the answer is:
Here is my best explanation:
'excessive drinking' is the definition.
'cleaner cup possibly' is the wordplay.
'possibly' indicates an anagram.
'cleanercup' is an anagram of 'crapulence'.
'leads to' is the link.
(Other definitions for crapulence that I've seen before include "sloshed" and "Drinking".)