Wipe the cabinet with a soft sponge to remove any cobwebs or dust. Gently wash it down with soap and water if any grime remains. Let it dry completely.
Add signs of distress, using a piece of fine-grit sandpaper. Concentrate the sanding around the edges and areas near the door for an authentic look. This process will remove some of the old varnish and give it an aged effect. Use a lint-free cloth or sponge to remove the paint dust once finished.
Paint shellac over the white cabinet to protect the wood, using a paintbrush. A thin coat will be enough. Make sure the clear coat covers the area that was sanded down.
Apply crackle medium with smooth, even paintbrush strokes. Generally for distressed white furniture, a thin coat of this glaze is enough. A thin coat produces fine cracks, while thicker layers will cause wider cracks in the paint. Let the glaze dry for an hour.
Paint over the entire surface of your cabinet with white paint and a paintbrush. Apply in the opposite direction that you painted the glaze on. White on white will not give a dramatic crackle finish. It will give a subtle distressed look.