Step one:
Canned lunch meat can be kept for 2-3 days if it is opened and put in the refrigerator. If you don't keep it in the refrigerator, you can't stay overnight, because staying overnight will make nitrite in lunch meat contact with oxygen, which is easy to produce sodium nitrate, which is harmful to human body, so you can't eat it.
Step two:
In summer, put the lunch meat in the refrigerator and put it on a plate, then wrap it in plastic wrap or plastic bag. Although it can last a little longer that winter, it is better to eat this processed food early. It can be used to make rice balls or sandwiches, and you can have a bite when you are hungry. You'd better finish all the lunch meat after opening it. If you can't finish eating, be sure to put the lunch meat in a container, then wrap the container with plastic wrap or plastic bag and put it in the refrigerator for preservation.