A: The only time we have come
across the
cups staining is if they have been washed in the dishwasher with items which have residues
of dark colored
sauces e.g. tomato or carrot or oil based foods.
1/4
cup shoyu (naturally brewed soy
sauce) or GF tamari 2 Tablespoons brown sugar 2 Tablespoons dry white wine (I also subbed rice vinegar once and it was great) 2 large garlic cloves, very finely chopped 1 teaspoon toasted sesame oil * 2 teaspoons unrefined, cold - pressed extra-virgin olive oil pinch
of crushed red pepper, or more to taste 2 1/2 pounds (or whatever you can get) grass - fed beef flank steak, cut
across the grain on a diagonal into 1 - inch thick slices or left whole (marinating can be longer if the steak is whole)