For each piece of leather husband, avoided strong chemical (8)
I believe the answer is:
peroxide
'strong chemical' is the definition.
(type of chemical)
'for each piece of leather husband avoided' is the wordplay.
'for each' becomes 'per' (I've seen this in another clue).
'piece of leather' becomes 'oxhide' (type of leather).
'husband' becomes 'h'.
'avoided' indicates named letters should be taken away.
'oxhide' with 'h' taken out is 'oxide'.
'per'+'oxide'='PEROXIDE'
(Other definitions for peroxide that I've seen before include "Hair treatment" , "Hair-bleaching fluid" , "Chemical used to bleach hair" , "Powerful bleaching agent" , "See 8" .)