wasn't showing up in "model" view, color will not change

Someone sent me a drawing that I need to work on (and need in black and white). At first, not everything was showing up in "model" tab but was in "sheet" tab. I think I have that fixed...I selected all and "explode" then changed all colors to white, also went into "layers" (there are many layers) and changed them all the white. However, some of the entities are still in different colors even though it shows "white" and "bylayer". Any help appreciated.