Combine cucumber, onion, bell pepper and jalapenos in a large, non-reactive (stainless steel or enamel-coated) pot. Stir in the kosher salt, stir to mix, then cover the pot and set aside in a cool place overnight.

Drain the cucumber mixture in a colander; rinse briefly with cold water and drain well. Return to the same pot and add the sugar, vinegars, garlic, crushed red pepper, turmeric, and celery seed. Cut a piece of cheesecloth about 8 inches square, add the pickling spices and whole cloves in the center, and tie into a pouch using kitchen twine; add the spice pouch to the pot. Bring to a boil over medium-high heat, reduce heat to a gentle simmer, and cook, partially covered, until the vegetables are tender and liquid is slightly thickened and very flavorful, about 25 minutes. Remove the spice pouch and discard. 

Relish may be cooled and stored in sterilized jars in the refrigerator for up to two months or processed in a hot water canning bath if desired. (See below.)

Makes 3 ½ quarts 

Note:  To store the relish in your pantry, fill sterilized jars with the relish, leaving 1/2-inch headspace. Wipe rims, apply lids and rings. Process in a boiling water canner for 10 minutes (starting time when pot returns to a boil). Remove jars from pot and let cool on a towel-lined countertop.

When jars are completely cool, remove the rings and test the seals. The relish is good to eat immediately. Store sealed jars in a cool dark place for up to a year.