When old paint chips, flakes, or peels, it leaves behind a
shallow depression. You'll need to repair these spots
before painting – new coats of paint won't hide them. Use
a fast-drying patching compound to fill the hole.
Scrape away any
loose paint with a putty knife or paint scraper.
Apply the spackling compound to the edges of the
chipped paint with a putty knife or flexible
wallboard knife.
Sand the patched
areas with 150-grit production sandpaper. The
patched places should feel smooth to the touch and
not have any edges. If the walls have a textured
surface you'll need to texture the patched areas to
match.