If the surface you are going
to work on is uneven from an old coat of paint,
it is advisable to rub the surface down with glass
paper to roughen it up, while removing any present
nibs.
Remove as much sheen as possible
from the surface, especially for timber or glossy
surfaces. This ensures the adherence of the fresh
coat of paint.
Next, wipe the sanded surface
clean with a damp cloth and allow it to dry before
painting.
There are various abrasive
papers in the market that can be used either wet
or dry. But those such as glass paper can only
be used dry.
Do note that when you are using glass paper on
your walls, you may want to halve it and then
fold it into a third. This helps improve the grip.
Alternatively, you can also use a sanding block.
