Step 1

Place the sliced cucumbers and onions into a large bowl and sprinkle the salt over the top. Fill the bowl with enough water to cover the cucumbers. Let stand for 8 to 10 hours.

Step 2

Drain and rinse the cucumbers and onion with fresh water. Sterilize 4 (1 quart) jars and lids.

Step 3

In a 6 quart pot, stir together the sugar and flour. Whisk in the vinegar, turmeric, mustard powder and celery seed to make a smooth paste. Add the cucumbers and onions and fill with enough water to cover. Stir, and bring to a boil. Cook until thickened, about 10 minutes, stirring frequently.

Step 4

Pour into hot sterilized jars filling to within 1/2 inch of the top. Seal with lids and rings. Process for 10 minutes in a simmering water bath. Refrigerate any jars that fail to seal properly.