Fill a bucket with hot water and add 1 tbsp. liquid dish soap. Mix until the water is sudsy. Clean the bookshelf thoroughly with a sponge and the soapy water. Rinse it thoroughly and let it air-dry for several hours.
Place a drop cloth under the Sapien bookshelf.
Sand the entire bookshelf surface with medium grit-sandpaper. This will rough up the old painted surface so that the new paint and primer will adhere better. Wipe the excess sawdust off the bookshelf with a damp sponge. Let it dry completely.
Brush one coat of primer on the bookshelf with a paintbrush. Make sure the entire bookshelf is coated. Use a thin but even layer of paint. Let it dry completely.
Dip a small paint roller into the paint and roll most of it off in a paint tray. Roll paint over large areas on the bookshelf, working from the top of the bookshelf to the bottom. Roll the paint on in one stroke and smooth it over with another. Don’t roll over one area more than this, as doing so can cause air bubbles and a rough surface. Continue until you’ve covered all of the large surfaces with one thin but even layer of paint.
Dip a paintbrush in the paint and remove as much of the excess as possible by sliding the brush along the paint lid. Brush the paint over any areas you were unable to reach with the paint roller. This includes the space between the bookcase spine and the shelves. Brush the paint on in one stroke and smooth it out with another. Oil-based paint will fill in brush lines as it dries if you don’t over-brush it.
Let the coat of paint dry completely overnight.
Repeat the painting process and let the bookcase dry completely.