Careless sandwich-maker? (13)
I believe the answer is:
butterfingers
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for butterfingers that I've seen before include "Someone prone to dropping things" , "Someone who drops things" , "He can't catch for toffee!" , "Careless person" , "Clumsy type" .)