In a large canning pot, heat the canning jars and lids in simmering water until ready for use. Do not boil. Set bands aside.
In a large stainless sauce pan, combing the vinegar, sugar and salt bringing the mixture to a boil, stirring to dissolve sugar. Add corn, red and green peppers, celery, onion, mustard, celery seeds and turmeric.
2 Cups white vinegar, ⅔ Cup Sugar, 1 Tbsp. salt, 4 Cups corn, 2 Cups red bell pepper, ¾ Cup celery, ½ Cup small onion, 1 Tbsp. dry mustard, 1 tsp celery seeds, 1 tsp ground turmeric
Reduce heat and simmer 15 minutes, stirring frequently.
Ladle the hot relish into hot jars leaving ½ inch headspace.
Remove air bubbles and wipe the rim of the jar with a clean damp towel. Center hot lid on jar. Apply band and adjust until fit is fingertip tight.
Place jar in boiling water canner. Repeat until all jars are filled.
Once the jars are all filled and in the water canner process them for 15 minutes, adjusting for altitude.
Turn off heat; remove lid and let jars stand 5 minutes. Remove jars and cool.
Check lids for seal after 24 hours. Lid should not flex up and down when center is pressed.