My wife likes to freeze bananas by removing their skin, wrapping them in aluminum foil, and placing them in the freezer. She eats a couple of bananas per day. So, this is using up a lot of aluminum foil. She tries to reuse the foil as much as possible. But, they get easily ripped after a couple of uses and we have to waste water washing them. Is there a way to freeze bananas that isn't so wasteful? For her to try it out, it will have to produce the same effect as using foil.
I freeze bananas in a plastic container, which I wash and reuse. I also wash and reuse Ziploc-type plastic bags, which work equally well, but don't last quite as long.
If your wife prefers aluminium, you can probably find an aluminium container (e.g. in an outdoor store), which should last you for several decades.
Like other fruits and vegetables I would just put them into a plastic container. It is practical to separate the pieces by plastic foil so that they can be easily separated in the frozen state.
Both the boxes and foils can be reused without washing for a limited time when kept in cold. Later they can be washed and reused again.
I simply freeze them, they don't need a container if you're going to eat them soonish (within a month, perhaps).
When you take one out if you run it under water for a few seconds the skin loosens up and they just pop out. I squeeze them into my smoothies.
If your wife eats them as a whole fruit, rather than in a smoothie, you can improve the condition a bit by putting them inside a slightly insulated container so they freeze more slowly. If you can slow down the speed of freezing they will crystallize less, making them seem a bit fresher when they thaw (the crystallization harms the cells and makes them mushy).