Here's another in my ongoing attempt to stop wasting everything.
I'm guilty of the following. You only need a tablespoon of tomato paste for a recipe so you open that little can, use a bit and then what do you do with the rest? You toss it. It's not expensive so why worry. Well, as we are learning it's not so much the expense but the energy it takes to produce something. Don't toss the energy, we're gonna need it later.
I tried buying those toothpaste-tubes of tomato paste and they aren't bad but I really didn't like the flavor all that much. I saw this on a cooking show and thought I give it a try.
Open your little can and remove what you need then spoon out the rest on waxed paper, freeze on a cookie sheet then, when frozen, pop into a zip lock bag and back into the freezer. Now when you only need a bit, fish this lump out, and toss in your pot. It melts quickly and you've saved some energy. The world will thank you.