I just found these great tips by students at Humboldt State University on the Appropedia website. This is the best system I’ve seen. Thanks for sharing!
Bottle bricks were made by using a tile saw to cut bottles harvested from the waste stream. The tile saw was set to cut the bottom 3inches of the bottle off. We butted the bottom parts of two bottles together and wrapped them in aluminum flashing and duct tape. The flashing acts as a reflector, sending light through the bottle and into the shed. Without the flashing, much light would be lost to the interior of the wall. We often used the butt of a clear bottle on the interior of the wall and a colored bottle on the exterior. This method allowed for brighter light to enter the shed.
Image credit Carrie Schaden