During coronavirus lockdown, I can't buy containers. But I've some empty boxes of Protinex powder like these: https://www.amazon.in/Protinex-400-g-Tasty-Chocolate/dp/B01MS489AE I guess it is made from metal.
So is it safe to store these things in it? Or it will be harmful to these things?
EDIT: I bought that product a long time ago, and now it seems like packaging is changed in the link I provided. So I'm afraid it would be not ideal to expect new answers.