One adult inside removes moisture in logs (7)
I believe the answer is:
diaries
'logs' is the definition.
'one adult inside removes moisture' is the wordplay.
'one' becomes 'i' (roman numeral).
'adult' becomes 'a' (abbreviation).
'inside' means one lot of letters goes inside another.
'removes moisture' becomes 'dries' (I've seen this before).
'i'+'a'='ia'
'ia' put within 'dries' is 'DIARIES'.
'in' is the link.
(Other definitions for diaries that I've seen before include "The Basketball _; Leonardo DiCaprio film" , "Personal journals" , "Personal records of daily events" .)