Sterilize 6 pint jars and lids in a boiling water bath for 10 minutes, then remove and let dry.

Dice 4 cups mixed peppers and 1 cup onions into small, uniform pieces using gloves for hot peppers.

In a large pot, combine the diced peppers and onions with 2 cups white vinegar, 1 cup granulated sugar, and 1 tablespoon pickling salt. Stir well and let sit for 10 minutes.

Place the pot over medium heat and bring to a boil, stirring occasionally, then reduce heat and simmer for 20 minutes to thicken.

Using a canning funnel, fill each hot jar with relish, leaving 1/2 inch headspace. Wipe rims clean with a cloth.

Place lids on jars and screw bands fingertip-tight to allow proper sealing.

Process the filled jars in a boiling water bath for 15 minutes, ensuring the water covers the jars by at least 1 inch.

Carefully remove jars with a jar lifter and place on a towel to cool undisturbed. After cooling, check that lids have sealed properly.