The smallest Lego thing I briefly owned was a thin, extremely small, piece of a metallic substance (as far as I know). Possibly about 10 mm long and 4 mm wide, this little sliver was apparently meant to separate a small battery and a light bulb during storage, to stop the battery being drained.
Lego set: Creator 31062 comes with a light brick. I unpacked the secondhand set bought in a thrift store, and checked that all pieces were present. Then wrapped it for a Christmas present for my grandson. After the celebration and cleaning up, I found this little thing. Vacuumed it away with the rest of the crumbs not even realizing what it was.
Lol, looking up light-bricks, I found that the little insert was a tab and was probably not classified as a brick proper, but is part of a new brick's packing. I wish we still had it to eke out the battery which emptied very quickly.
I expect that there are more such extremely small but important components and so wouldn't tip everything into a mesh bag in the first instance. Get some shoe box lids and chocolate boxes and their lids. Spread new components in a single layer. Do a rough sort: big, medium, small into different mesh sized bags. The grit left will be the tinies. Use a linen bag to wash these. Good luck not throwing out tabs!