Last of all, removed unsightly urine stain (3)
I believe the answer is:
dye
'stain' is the definition.
(thesaurus)
'last of all removed unsightly urine' is the wordplay.
'last of all' says to take the final letters.
The last letters of 'removed unsightly urine' are 'DYE'.
(Other definitions for dye that I've seen before include "Colour (fabrics)" , "Colourant" , "Colouring material" , "Colouring matter" , "Colouring agent" .)