Brilliant finish in outskirts of Czech capital (6)
I believe the answer is:
chrome
'brilliant finish' is the definition.
(I've seen this before)
'outskirts of czech capital' is the wordplay.
'outskirts of' means to remove the middle letters (only letters on the outskirts).
'capital' becomes 'rome' (capital of Italy).
'czech' with its centre removed is 'ch'.
'ch'+'rome'='CHROME'
'in' is the link.
(Other definitions for chrome that I've seen before include "Plate (for bathroom fixtures etc)" , "A yellow colouring matter" , "'Silvery metal, resists tarnishing (6)'" , "Metal plating - type of yellow" , "Feature of bath taps" .)