Thanks much. Ok, plastic, then foil. I will give this a try.
I'm at my parents' house, trying to convince my mother to let me cook some dishes that I can freeze so they can thaw and eat them later. (Her cancer is making her nauseous and uninterested in food--particularly meat--but she still needs to eat and so does my dad!) She seems oddly resistant to this, but did ask if I could bake and freeze an angel food cake, so I'll start with that.
I should probably stop asking for permission and just do it, but old habits die hard. It's like I'm ten again!
Anyway, thanks for the advice.