Ace tips to make germ free (7)
I believe the answer is:
aseptic
'germ free' is the definition.
(I've seen this in another clue)
'ace tips to make' is the wordplay.
'to make' indicates anagramming the letters.
'ace'+'tips'='acetips'
'acetips' anagrammed gives 'ASEPTIC'.
(Other definitions for aseptic that I've seen before include "Free of bacterial or viral contamination" , "Free from bacteria, surically clean" , "Free from harmful bacteria" , "ideal conditions for hospital?" , "Free from bacteria, surgically clean" .)