I have the shelburne which i think is pretty close to the manchester, my glass is always getting dirty on the lower corners more then the rest! Once i get a couple years worth of seasoned wood ill see if it changes. The ash pan i believe is the same which i dont use either! Just the other day i decided to try it, the grates were closed and it was a pain to get them open which led me to pull the top one off. I think im gonna make a steel plate with a square plug like i saw somewhere here. The open back to me just makes dumping into my metal can easier!