Allow the corn ears to dry on the stalks as long as possible before a frost. If they can stay on the stalks for four to six weeks, they are better off for next year's seeding. If you must harvest earlier, first let the husks turn brown. Use a paper bag for transport, as the ears of corn cannot breathe in plastic bags.
Peel the husks back and hang the ears up to dry in a cool, dry place. Wait until the ears are thoroughly dry and the seeds are shriveled before harvesting.
Place a screen underneath the place where you will harvest your seeds. Twist the corn between your hands, which will make the kernels fall onto the screen. Gently blow away any husks or other debris that might be on the screen.
Store the seeds in a container. Make sure they remain dry and unharmed for next year's growing season.