The ceiling is a bleached carpet to begin with. A mixture of 80% water and 20% bleach will bring it back to like new. You MUST hold a large towel under the spot you are doing and DO NOT get any drips. I have done dozens and never had a problem.
1998 Pace Arrow 35 ft. F53 Ford V10 2012 Honda Civic toad
32 years mechanic at Delta Air Lines 15 year motorhome service manager. 3 popups....2 travel trailers....5 motorhomes....loved them all.