Surplus of clothing size to be picked up (6)
I believe the answer is:
excess
'surplus' is the definition.
(synonyms)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for excess that I've seen before include "Subjugate by force" , "Glut, superfluity" , "Over and above what's needed" , "Nothing in it, for the Greeks" , "Too much - going too far" .)