Wash hands with soap and water.

Peel and chop the onion.

Chop the celery.

Peel the potatoes, and cut them into small cubes.

Melt the margarine in a large saucepan on low heat.

Add the onion and celery. Cook for a few minutes.

Add the potatoes, salt, pepper, and 1 1/2 cups water.

Cook for 15 minutes until the potatoes are tender.

In a small bowl, stir together the dry milk and flour.

Add 1 1/2 cups water slowly, stirring as you add it.

Add the milk mix to the potatoes.

Cook until the soup is heated and slightly thickened.