Once canned beans are opened, they become perishable and should be either prepared properly, consumed, or refrigerated. To preserve flavor, transfer the canned food to plastic or glass containers before refrigerating. Leftovers should be consumed after 3 to 4 days of refrigeration. Freezing your extra canned beans should be fine. In fact, I often make a big batch of chili (using canned beans), and then freeze some of it with no change in quality. Simply store your extra beans in a heavy plastic container or plastic freezer bag and use within 6 months.