Don't know if this will work for your recipe, but I've made tomato sauce and added too much salt. This worked! I sliced one raw peeled potato into the sauce and continued cooking the sauce-worked like a charm. I removed the potato before I served the sauce. The potato was delicious too! It's an old trick.
You could try it in your salsa. Do you cook your salsa; maybe it would work. I'd love to have your recipe too! Good luck!
I don't know if I can help you with the current batch but if you'll share the recipe you use here it will be easy to figure out how to adjust and 'maybe' be able to save the current batch ;-)
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