Manchester (UK) is full of berries. You see them on trees, shrubs, everywhere. Nobody gives them a second thought. See for yourself:
And what do you do with all these berries?
Household remedy for cold. Harvest them, clean them, crush them, then a secret sauce of lemon and cranberry juice is used to soak them, and then a bit of heating and filtering. Finally, you get ‘Fire-water’, which is a remedy for flu!
A friend prepared a bottle of this potion for me. And it works! Photograph below. 
The potion tastes somewhat like the ginger-lemon drink of old Bombay but is more astringent.
Manchester, UK, 2021Nov27
