We seem to search for items in random assortments most successfully by colour (rather than eg by shape alone). Try looking for a big brass screw in a box of small grey ones). Today’s invention is a way to ensure than new screws are findable, even when tipped into a box of various random fixtures.
A small ring of paint, of a colour unique to a given design of screw, would be sprayed onto the threads (not heads) of all of the new screws of that type during production in the factory.
They could all later be tipped into one’s screws/nails/sundry small parts bin.
Looking for eg three purple screws would then be made very much easier when staring into the box.