Celebrate Luton? Put a rosy gloss on it (5,3,4,3)
I believe the answer is:
paint the town red
'celebrate' is the definition.
(to paint the town red is to celebrate hard)
'luton? put a rosy gloss on it' is the wordplay.
I cannot really see how this works, but
'luton?' could be 'town' (Luton is a town) and 'town' is present in the answer.
'a' is found in the answer.
'rosy' could be 'red' (I've seen this in another clue) and 'red' is found within the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for paint the town red that I've seen before include "Celebrate" , "enjoy celebration" , "Go on a pub crawl" , "get rid of the blues?" .)