We live in a single wide mobile home. Our ceilings our popcorned and we hate it. My spouse hates it more than I because they are are impossible to clean. Without tearing ceilings down and applying new drywall, what can I do? I have learned that the walls are not drywalled just some very thin plywood like material. Are the ceilings the same?

I recent got a house that had been abandoned for several months. some windows were knocked out and a door was kicked in, after repairing those and waiting a month to make sure i wasn't wasting time i have decided to start doing more. the walls have been egged. they have been basically baking in the Oklahoma heat (100+ most of this month) and at least the previous month. How can i clean/remove the egg w/o causing too much damage to the drywall? the people at Lowe's suggested just sanding it down with a real fine sandpaper, while Home Depot said soap and water followed by an oil based primer.