First off -- my 5 kids "inherited" my Lego collection. That is, Lego sets that have accumulated in a large blue tub from when I was their age. I can't say how many there are...but it's a lot. Finding small pieces is a pain, you have to literally dig down to the bottom of the tub and hope you spot *and* snatch the piece before it's again lost in the fray.
It is for this reason that I created Lego sorting boxes. This isn't a new idea, in fact you can pick up a set for around $40. I had some extra wood lying around so I decided to give it a shot. I found that 5/8" diameter holes were good for the small pieces, 1" holes for the medium pieces. So far I've assembled two of the 3 boxes and initial tests worked great. The kids had a blast sifting for "treasure" and couldn't believe that it actually worked.