I bought a 2-pack of the Big Block XL Lump Charcoal based on a prior experience.  The two bags arrived in a box, and while one bag was excellent with nice huge chunks, the other bag was nothing but small pieces of lump and a few chunks of what looked like hard clay or concrete.  I can understand that shipping may cause the lump to break down a bit and this is out of KJ's control, but I was disappointed in the number of chunks of clay that I found in that same bag.