We can for many reasons, the main one is because it taste better than store bought canned tomatoes but also to reduce waste, transportation pollution, and it's a lost art in our opinion that we'd like to continue. We use these through out the fall and winter in tons of dishes so they are never on the shelf for very long. We're actually planning another canning session soon so we have enough to last till next year.
Below is just a quickie course in canning. You'll need to sterilize your jars and figure how long the process time will be in your area.
The first thing we do is core the tomatoes.
Next we carve an X in the bottom to help with peeling the skins.
Beautiful tomato shot
They then get placed in a large pot of boiling water for a 2-3 minutes to loosen the skin. We do this outside to keep the heat out of our house.
The tomatoes are then put directly into an ice bath to stop the cooking, you don't want mushy tomatoes!
The skins are then peeled and should come off very easily.
We've found that the larger you can keep the tomato the better the flavor. Whole tomatoes are even better but you can quarter, diced, or crush them before adding to the sterilized jars. Top with a sterile lid and process in a pressure cooker or canner.
We ended up with around 18-20 jars (pints and quarts) from the box we got.
To read up more on canning fresh produce check out this link!