Remove the papery husks and rinse the tomatillos well under clean running water.

Place them into a large sauce pan, and add enough water to cover the fruit by a few inches.

Bring the pot to a boil over medium-high heat, and cook the tomatillos until they are just tender, about 5 to 10 minutes. Keep hot.

Cover your counter with a towel. Use the jar lifter to take one jar out of the canner. Pour the water into the tomatillo pot, and set the jar on the towel. Keep the rest of the jars inside the canner so they stay warm.

Add 1/2 teaspoon citric acid or 2 tablespoons lemon juice to each quart jar. Add 1/4 teaspoon of citric acid or 1 tablespoon of bottled lemon juice to each pint-sized jar.

Position the canning funnel on the jar. Use a slotted spoon to fill the jar loosely with tomatillos, and then top off with hot cooking liquid leaving a 1/2-inch headspace.

Run the bubble popper through the jar to release trapped air bubbles, and adjust the headspace again if necessary.

Wipe off any residue from the jar rim with a damp towel. Place a lid on top of the jar, position the band over it, and gently screw it on until fingertip tight.

Place the filled jar back into the canner and repeat the process for the remaining jars.

Once the filled jars are in the canner, adjust the water level to cover the jars' tops by at least two inches.

Cover the canner and bring it to a boil over high heat. Once the water boils vigorously, set a timer and process pint-sized jars for 40 minutes and quart-sized jars for 45 minutes at altitudes of less than 1,000 ft. Adjust processing time for your altitude if necessary. (See notes)

When the processing time is complete, turn off the heat, remove the cover by tilting the lid away so that steam does not burn your face, and allow the canner to cool down and settle for 5 minutes before removing the jars.

Once the filled jars are in the canner, place the lid on the canner and lock it. Leave the vent open and bring the canner to a boil over medium-high heat.

Let the pressure canner vent steam for 10 minutes, and then place the pressure regulator on the air vent allowing the pressure to rise.

When the canner has reached the correct pressure (10 pounds for weighted gauge or 11 pounds for dial gauge pressure canner), set a timer and process both pints and quarts for 10 minutes at altitudes of less than 1,000 ft.

Adjust the pressure for your altitude if necessary (See notes), and regulate the heat as needed to maintain a steady pressure.

When the processing time is complete, turn off the heat, and allow the canner to stand undisturbed until pressure drops to 0. Once the canner is depressurized, let the canner cool additional 10 minutes before removing the lid, and then let the jars settle for an additional 10 minutes to adjust before removing them.

Spread a dry towel on the counter, use the jar lifter to remove the jars from the canner, and place them on the towel. Keep the jars upright, and wait to tighten bands or check the seals. Let the jars sit undisturbed for 12 to 24 hours to cool.

After 12 to 24 hours, check to be sure the jar lids have sealed by pushing on the center. The cover should not pop up. The jar failed to seal if the top flexes up and down. Refrigerate it and use it within a few days.

Once you have checked the seals, remove the ring bands and wash the jars in warm soapy water. Label, date, and store them in a cool, dark place. Use within 12 to 18 months for the best quality. Once the jar is open, refrigerate it and use it within a week. Yields about 4 quart jars, or 8 pints.