OK I used a solution of TSP after all the peeling paint was scrapped off I am down to a smooth hard white finish that has a bit of a sheen on it where ever it is not chaulky. the more I wash and rinse the more chaulk. As a matter of fact the paint I put on 2 years ago was Benjamin Moore ceiling paint. I also washed the ceiling with the TSP before I painted the ceiling as well The TSP was the same box the hardware sold me 2 years ago. No Paint appears left on the surface. As far as insulation it does not apply as there is a second story bedroom above the kitchen. This is the only smooth ceiling in the house all the others were the 60's swirl in the plaster coat and paints great.