Half-eaten taco filling in recycle bin? (4)
I believe the answer is:
icon
'recycle bin?' is the definition.
(recycle bin is an example of an icon on computers)
'half-eaten taco filling in' is the wordplay.
'half-eaten' indicates taking half.
'filling' indicates putting letters inside.
'taco' cut in half is 'co'.
'co' going into 'in' is 'ICON'.
(Other definitions for icon that I've seen before include "Devotional image (C, not K)" , "Idol" , "On-screen image" , "Famous and admired person" , "hero!" .)