Wash jalapeños, cut off stem tops and then slice into 1/4" rings. Cut each garlic clove in half.
Fill each of 6 to 7 clean, warm pint canning jars with sliced jalapeños and 4 garlic clove halves (2 cloves for each jar), leaving about 3/4-inch of headspace.
In a large saucepan heat the vinegar, water and salt to boiling and then reduce to a simmer while pouring into jars.
Use a ladle to pour the vinegar mixture over the peppers, leaving 1/2-inch headspace if canning- headspace doesn't matter for refrigeration, just cover the jalapeños with the liquid.**
Wipe rims and attach two piece lids (if refrigerating, you can reuse old lids, but always use new lids when water-bath canning).
Label and refrigerate.***
To seal these in a water-bath canner to store on the shelf (though they won't be as crisp): process the jars for 10 minutes, turn off canner and remove lid but leave jars in for 5 minutes more before transferring them to a towel-lined surface. Let cool without disturbing for 12-24 hours before checking seals, labeling and storing in a cool, dark place.
*White vinegar is okay, too, but apple cider vinegar is a bit more mild.**If your jars aren't packed tightly with jalapeños, you may not have enough brine - simply boil up a bit more to cover.***We've kept the jalapeños for up to a year and they've been great.