We bought my in-laws house a few months ago. The powder room doesn't have a vent fan (yeah, I know, something we're going to correct very shortly). For the past 32 years that my in-laws have been living here, my MIL has burned scented candles to keep the....errrr....fragrance down. ;o) Unfortunately I now have 32 years worth of waxy smoke residue on the ceiling. I tried to clean it with a mop and some detergent and it made a horrible mess...even down the walls. That mess is now impossible to clean off.

I have to paint the powder room....any suggestions on what I can use to clean it off so that the paint can stick??

And PLEASE don't say I need to redrywall the ceiling.

Thanks in advance.