TIP: if you want a milder salsa, you can skip the jalapenos and use 1-1/2 cups of milder peppers. If you’d like it spicier, decrease the mild peppers to 3/4 cup and increase the jalapeños to 3/4 cup. You can play around with the types of peppers you like best, just not the amount – a total of 1-1/2 cups of peppers for one batch is the limit for safety.
You did forget one important detail however in the sanitizing.. YOU HAVE TO SANITIZE THE LIDS, and do not touch the rubber part of the lid as your oils in your skin will cause it to be unusable. I have canned for years, as does my mother in law.. I would not hesitate to can ANYTHING, meat or veggie.. :) Just remember to sanitize the jars and lids!!
Preheat the broiler. Put the quartered tomatoes, sliced onion, and whole garlic cloves onto a roasting tray, spreading out evenly. Drizzle with plenty of olive oil and season well with salt and pepper and sprinkle with cilantro sprigs. Broil until everything is nicely charred, about 10 minutes (you want lots of deep rich color so don't be afraid if some of the edges get pretty black).
Combine all ingredients except cumin, oregano, and cilantro in a large pot and bring to a boil, stirring frequently, then reduce heat and simmer for 10 minutes. Add spices and simmer for another 20 minutes, stirring occasionally. Ladle hot salsa into pint jars, leaving 1/2-inch headspace. Adjust lids and process in a boiling-water canner for 15 minutes at 0–1,000 feet elevation, 20 minutes at 1,001–6,000 feet, and 25 minutes above 6,000 feet.