I save salsa jars to reuse as sealable containers. A cooking experiment that I've tried before is to microwave pasta in them.
1. Fill the container half full of pasta. It is better to not use more than half because the pasta will expand.
2. Fill the container with pasta sauce. Replace the lid and shake it up. This will get rid of air bubbles that will want to expand and explode in the microwave.
3. Remove the lid and add a little water. This will help the pasta to cook.
4. Microwave to a full boil. This takes 2 to 2.5 minutes in my microwave.
5. It will be too hot to handle. Let it cool for 16 minutes. During this cooling period, the pasta will cook. This will make a delicious single serving that is just the right temperature for eating. You can eat out of the same container.
6. In theory, you could microwave multiple containers at the same time.