First, clean your jars and lids using a steamer rack in a 16-quart pot. Place the jars on the rack and fill the pot with water, enough to cover the jars. Do not let the jars touch the bottom of the pot, as the heat can cause the glass to crack.
Bring the water to a boil and boil the jars for 10 minutes. Remove the jars with tongs when you’re ready to use them.
Prepare the candied jalapenos per the instructions above.
When the candied jalapenos are ready, scoop them into the jars, leaving ¼ inch head space.
Clean the lids with soap and hot water, then place them onto the jars. Secure them with cleaned canning rings. Wipe the rims clean.
Place the filled jars back into the hot water bath, onto the steamer rack, ensuring the jars are covered with 3 inches of water.
Return the water to a boil and process them for 10 minutes. For higher altitudes, process them for additional time (at least an extra 10 minutes). Remove the jars with tongs and tighten the screw caps.
The jar lids should make a popping sound as they seal. If a lid doesn’t seal for some reason, you can reprocess it, or store the jar in the refrigerator.
Invert the jars to test for leaks. Flip them upright after 10 minutes and allow to cool.
Store the jars in a cool, dry place. They will last a year or longer this way. Once you open them, however, keep the jars in the refrigerator.