here is a simple way to pan for lego bricks. though it is time consuming it is tons of fun and very efficient.
Step 1: First Get a Pan. (or a Small Plastic Box)
Step 2: Getting the Bricks.
next you want to get a source. (pic 1) then fill your pan. (pic 2) after that you look throuh the pan and dump your excess bricks.
Step 3: Finishing Up
im sure youll be pleased if you had a big source.