Cheers up after receiving slipper as lucky charm (6)
I believe the answer is:
amulet
'lucky charm' is the definition.
(I've seen this before)
'cheers up after receiving slipper' is the wordplay.
'cheers up' becomes 'at' (I've seen this in other clues).
'after receiving' means one lot of letters goes inside another.
'slipper' becomes 'mule' (mule is a kind of slipper).
'at' placed around 'mule' is 'AMULET'.
'as' acts as a link.
(Other definitions for amulet that I've seen before include "Jewel to protect from witchcraft" , "Piece of jewelry thought to be a protection against evil" , "Lucky ornament" , "Mascot" , "Protective trinket" .)