How I get all my little babies out is pretty simple in my opinion. It takes like 5 minutes. I first take all my egg crates out of my colony tub and move them to another temporary holding tub. This leaves me with nothing but the frass at the bottom of the first tub, with a bunch of baby roaches running around in it and some big ones here and there. I grab all of the bigger ones up by hand and place them into the second tub where my egg crates are chilling for the moment.
Now, for the itty bitty babies. I have a plastic Tupperware container that I bought and I cut out most of the lid and replaced it with a giant sheet of
plastic canvas, the stuff they use to make all sorts of
neat crafts with (as seen in my hyperlinks). The sheets are very cheap, a couple dollars at most at a local craft store. Put the modified lid onto the rest of the Tupperware container, and lets' begin.
I take the frass remaining in my roach colony and pour it over the lid of the Tupperware container. The holes in the plastic canvas are pretty small, but they are large enough to allow 95% of your frass to fall through into your Tupperware container. The baby roaches are too big to fall through the holes in the plastic canvas, so they stay on top while most of your frass falls into the Tupperware container below.
This leaves all your baby roaches on the lid of the container with a few pieces of frass here and there. Take that lid, and dump all those babies and very few pieces of remaining frass into the container where the egg crates and the big roaches are being held temporarily. Do this over and over. It takes about 5 minutes for me to do a whole colony that way. I dump as much frass as I can onto the lid of the Tupperware, shake the Tupperware a tad to allow the frass to sift through to the bottom, then I dump the remaining roaches and bit of frass into the holding tub. I do this until all frass has been sifted through, which will leave my original roach colony tub all bare bottom. I wipe it down with water and soap, then rinse a few times and hand dry. I never use chemicals on it because I don't want any residue leftover to harm my roaches. The cleaning with soap does just fine.
After original colony tub is clean and dry, I dump all the roaches from the 2nd bin back into their original colony tub.
Voila. Easy as pie and pretty simple to do. No complicated sorting bins or anything. Just a simple Tupperware container and a big cheap piece of plastic canvas, and some hot glue to modify it all.