Are their contributions pint-sized? (6)
I believe the answer is:
donors
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 donors that I've seen before include "Givers as of blood" , "They give, money or blood" , "presenters" , "They give to others, maybe blood" , "They give things including blood" .)