This can also be the case when rinsing a stain out of clothing, if you've spilled something on your clothes quickly rinse it under cold water. Hot/warm will set the stain making it harder to remove.
Spray the bowl with Pam/canola oil spray before storing in the fridge. Makes it even easier to wash and keeps the spaghetti from getting very dry from the microwave
I sell Tupperware and our Crystalwave bowls have a stain guard that helps them from not staining. Personally i would forget to rinse the bowl first and also wouldn't the heat from the spaghetti heat the bowl up so it would stain? That is why I love the Crystalwave brand. If anyone wants info on costs I would be more then glad to help. Thanks for taking the time to listen.
You're welcome.