Out of some wonder, the peanut butter in our area comes in plastic jars, meaning that it is lighter than a normal jar. I save these plastic jars during the year and use them later on hikes.

Also, in the local grocery stores I can buy some dairy products which come in plastic buckets and boxes (like this one, this or this) - I save these for trips and hikes: they can be easily packed into each other, or I can fill them with other objects (berries I pick from the forest, socks or anything else) after they get empty. They also hold liquids quite well, although I use a plastic bag to be sure there would be no leaking. Also, in case they become redundant I am not so sorry to dispose them as if I would be for a tupperware box.

Out of some wonder, the peanut butter in our area comes in plastic jars, meaning that it is lighter than a normal jar. I save these plastic jars during the year and use them later on hikes.

Also, in the local grocery stores I can buy some dairy products which come in plastic buckets and boxes (like this one, this or this) - I save these for trips and hikes: they can be easily packed into each other, or I can fill them with other objects (berries I pick from the forest, socks or anything else) after they get empty. They also hold liquids quite well, although I use a plastic bag to be sure there would be no leaking. Also, in case they become redundant I am not so sorry to dispose them as if I would be for a tupperware box.