Clean close to aisle in upturned seats (5)
I believe the answer is:
sweep
'clean' is the definition.
(sweeping is a kind of cleaning)
'close to aisle in upturned seats' is the wordplay.
'close to' indicates one should take the final letters (the close/ending of).
'in' indicates putting letters inside.
'upturned' is a reversal indicator.
'seats' becomes 'pews' (pew is a kind of seat).
The final letter of 'aisle' is 'e'.
'pews' written backwards gives 'swep'.
'e' put within 'swep' is 'SWEEP'.
(Other definitions for sweep that I've seen before include "Stroke at the crease" , "Brush; rush" , "Long oar" , "Windmill sail" , "Clean the floor" .)