Combine zucchini, onion, green pepper, and red peppers in a large bowl. Sprinkle with salt. Cover with cold water. Let stand two hours. Do not stir.

Drain veggies, rinse with cold water, and drain again.

In a large saucepot, combine sugar, celery seed, mustard seed, and vinegar. Bring to a boil.

Stir in veggies and let simmer for 10 minutes.

Pack into jars leaving 1/4 inch headspace. (I've discovered this recipe can get a little "watery" depending on the type of zucchini used, so I usually drain a bit of the liquid on the side of the pot as I'm ladling it into the jars) Add lids and process for 10 minutes in aboiling water-canner.

Remove from water-canner and place on towel on counter and allow to cool for 24 hours. Check lids to make sure they are sealed. (the middle button will not pop back up when pressed)

Store for up to one year.