I hate to throw anything out including screws,nails, etc. if in good shape. Just yesterday I needed to replace the flashing at the bottom of my rear garage as it gotten ripped off when they removed the old concrete slab. Seems the previous owner used very short screws and that's why it was so easy to pull away from the building. Anyway, went to my trusty dish I throw odds and ends screws and found longer ones to replace the shorter ones. And yes, I threw the shorter ones into the trusty dish for a future project.
As to sewing items, if I remove them myself I will throw them into the drawer next to the machine so I know it came from that particular machine cause I know the next time I open the drawer and wonder where it came from I'll know its something from that machine and not the other machines. Short term memory here so need all the help I can muster at times.