Zucchini Pickle

9  cups sliced Zucchini or cucumbers
2  large sliced onions
2  tablespoons pickling salt
1  cup sugar
1  cup vinegar
1  teaspoon celery seed
1  teaspoon mustard seed (optional)

Stir Zucchini, onions and pickling salt together and put into a container. Mix the sugar, vinegar, celery seed and mustard see together and pour over the slices. Keep in refrigerator. Let stand several weeks before eating.