Try removing odd bits of radium (3)
I believe the answer is:
aim
'try' is the definition.
(thesaurus)
'odd bits of radium' is the wordplay.
'odd bits of' means one should take alternating letters.
The alternate letters of 'radium' are 'AIM'.
'removing' is the link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for aim that I've seen before include "Attempt" , "Point or direct, a weapon say" , "Direct, intend" , "Point (gun); intention" , "Point (a camera)" .)