Pour ivory or pale yellow paint into a paint tray. Cover the walls with a coat of the ivory paint. Allow the paint to dry thoroughly.
Pour denim glaze into a new paint tray. Paint the wall with glaze with a paint roller. Use enough glaze to completely cover the pale layer underneath.
Hold a wallpaper brush at an upper corner in the room. Hold the bristles firmly against the still-wet glaze and brush down the wall to the bottom. This will create lines in the glaze and show the paler paint beneath. Brush lines down the entire wall from one side to the other.
Brush lines across the wall using the same technique. Vary the places where you place horizontal lines. Stop halfway across in some spots, then go all the way across in other stripes. This will mimic the uneven look of worn denim.
Run a check roller up and down on various random spots over the wet glaze. This will create more worn-looking spots in the glaze, completing the denim look. Allow the walls to dry completely before replacing the furniture in the room.