Paint the paintbrush bristles and the gold metal with white paint. Let dry. (You could just dunk it in a cup of white paint if you were doing lots)
Tie a piece of twine in the paintbrush loop at the top.
Cut a triangle out of fabric. Put a strip of hot glue on the edges and around the front of the paintbrush and stick the fabric on. Glue the extras on the back.
Put a dot of hot glue where the fabric meets the brush and stick the wooden ball on for the gnome's nose.