Thoroughly sand the vanity surface with 150-grit sandpaper. Use a tack cloth to remove all dust from the piece. Remember to sand the handles and other wooden accessories.
Mix the milk paint powder with equal parts warm water. Mix the paint thoroughly and set it aside for about 10 minutes to thicken slightly.
Milk paint works best when mixed with room-temperature water. For a unique color, mix two colors of milk paint powder before adding water. Make a note of the "recipe" to re-create the same color later. Use the time while the paint thickens to do any last-minute sanding.
Seal the vanity with a non-toxic, clear-coat acrylic sealer. Water will leave spots on unsealed milk-paint surfaces.
Use thin coats of acrylic sealer; the sealer can dry milky white if applied too thickly or if the room is too humid.Install the vanity as desired, hooking up the drain line and water supply.