When I purchase bulk LEGO bricks, one of the first things I do is to tip the whole lot into a mesh bag and give them a good soak in the bath (of course, I remove all the electrical bits etc. first). This usually gets rid of most of the accululated muck etc.

However, I am concerned that the very smallest pieces will slip through the net and end up getting lost en route to the bath or even disappear down the plugh hole.

The solution is obvious: to make sure that I use a bag with small enough holes that the smallest pieces can't fit through.

What, therefore, is the smallest component that LEGO have made?