New surfaces
New plaster or patches must be cured, clean, dry and not chalking. If mold is present, treat the surface with a suitable healing c treat the surface with a suitable healing cycle. Remove by brushing or washing same efflorescence. Prime clean surfaces with water based acrylic primers, preferably a type solvent.
Painted surfaces:
Remove the parts paint to flake away: in the presence of lime based paints or tempera, perform the total removal by washing and brushing.