The packs of crème fraîche, sour cream, 500gr. Yoghurt etc. used to come with a practical plastic lid that could be used to close the pot and put it back in the fridge after opening, as you rarely need the whole contents of the pot at once. Unfortunately, these packs were gradually converted to aluminum lids. It's a great pity, as this makes it much more cumbersome and you need an additional tool to close the cup and put it back in the fridge. I have not yet found a practical and environmentally friendly solution.