i only throw away itty bitty edge cuts and anything smaller than 1/2"...the little pieces, smaller than a 2 1/2" piece i put into a box for the local preschool; they use them for collages and also make what they call treasure boxes...each child brings in a box with a lid (like a shoe box) and they put glue all over the sides and top of the box then cover them with fabric bits...the kids love making them it is one of their favorite craft projects.
i throw away strings/threads; but anything i think kids in school can find a use for i donate. teachers do not have budgets anymore to pick up supplies for their classes. you do not have to save so much there is a storage issue, when i get a box or basket full i just bag it up and drop it off. or i send to people here who are requesting scraps.
i need to live at least 200 more years to make a dent in my projects :) i have to pass some on...