Summarize this article:

Pick out a few ears that are at the ideal stage of ripeness for eating fresh and remove the husks and all traces of remaining silk. While you're shucking, heat a large pot of water until it just begins to boil, then add the corn. At the 3 minute mark, remove the ears from the pot carefully and set them aside on a layer of paper towels to cool. Leave the blanching water to continue boiling. You'll be using it later to pack the corn for canning. Allow the corn to rest until it's cool enough to handle. Then, stand each ear vertically on its end and run a knife down the side to loosen the whole kernels from the cob. Use a large bowl to collect the kernels as they fall, or scrape them into the bowl from your cutting board.  Be careful not to let the blade of the knife scrape against the cob. This can release a starchy liquid from the kernels, which may impact the flavor of the canned corn or it's ability to be safely preserved.  An electric knife can come in handy for making quick, clean cuts. If one of these tools isn't available, you can use either a smooth or serrated blade, provided it's sharp enough to avoid mangling the kernels. Spoon the kernels into the mouth of each jar, leaving 1 inch (2.5 cm) of space at the top. Give the jar a shake to help the corn settle. Avoid packing or compressing the kernels, as this may damage them.  It will take about 2.25 pounds (1,020 g) of whole corn, or about 4 average-sized ears, to fill 1 US-pint (470 ml)-sized canning jar. Double that amount for quart-sized jars.  Heat your canning jars under a stream of hot water before adding the corn. This will prevent them from cracking or shattering when you add the boiling canning liquid. The exact temperature isn't that important as long as the jars are still warm to the touch when the corn goes in. Though it's not a strict requirement, a little bit of salt can help preserve canned goods more effectively and for longer periods. For pint jars, a ½ teaspoon pinch will do. For larger quart-sized jars, you can use up to 1 full teaspoon. Use granulated iodized salt or kosher salt only. Pour the hot liquid steadily into each jar until it reaches the top layer of kernels. Avoid overfilling the jars—once again, you'll want to leave about 1 inch (2.5 cm) of headspace. Let the jars sit open for 3-5 minutes to cool slightly and allow trapped air bubbles to escape.  It may help to use a funnel or ladle to safely get the boiling liquid from the pot to the jars. Overfilling may cause the jars to burst when they're subjected to intense pressure. Place the jars in your canner and lock the lid, leaving the heat vent open. Adjust the canner to the appropriate pressure setting specified by the model and start it up. Once the steam stops escaping, close the vent. Pint jars should process for 55 minutes, while quart jars will need about 85. Afterwards, you can cool them off and put them into storage. When preserved by canning, sweet corn will stay good for a year or longer.  The exact pressure level you use will depend on the quantity of corn you're canning, as well as your location. As a general rule, however, you'll want to keep it somewhere between 11–13 pounds (5.0–5.9 kg).  Alternatively, you can do your canning the old fashioned way by submerging the sealed jars in boiling water until you hear the lids pop.

Summary:
Blanch the corn for 3 minutes. Cut the kernels off of the cob. Fill canning jars with the corn kernels. Add ½-1 teaspoon of salt if desired. Fill the jar with the blanching water. Process the jars in a pressure canner.