Depends on the paint already on the wall. Is there a shine and feel smooth. Or does it look dull with a grainy texture. If its shiny and smooth dishwashing soap and a rag will do wonders. If its flat paint its look terrible taking a wet rag to it, but itll be fine to paint over.

The ceiling will almost definitely be flat and possibly textured. If its textured then itll have to be scraped. But dont do that if your home was built in the 80s or prior. Asbestos could be present.

My first job was doing insurance claims like fire and water damages. Did it for over six years. If you have any other question go ahead.

[–] dingdongitsabear@lemmy.ml 1 points 2 days ago

it's the usual lime-based paint with god knows how many layers underneath.

thanks a bunch. I've made a separate post, here it is: https://lemmy.ml/post/24996046