I wonder if the plastic breaks down and the stain gets enmeshed somehow. I had a clear glass coffee cup that kept getting coffee stains and it was textured. Someone suggested to me that the stain was seeping into the design. As an aside, the textured glasses seem to be a good idea for elder people in terms of grip.

Any plastic you microwave will be ruined and set tomato stains in it. Stainless steel for any tomato base food.

Spaghetti noodles and sauce companies don't have the world wide government funded dollars that pay for the real dawn.
That's the Paris accord green new deal dawn they use on ducks.
Not the get the spaghetti off your shit dawn you buy in the store.
You gotta spend the big bucks to get thet David Suzuki style stuff.

OVER A BARREL

Palmolive dishwasher liquid works but the stores here don't carry it anymore.