As far as I understand, colatura's basically Italian fish sauce, so you'd use it to add something savory to sauce or soup etc. Or wherever you might use anchovy paste.
The problem is I have a 5 oz. bottle of the stuff - a neat souvenir someone gave me from their trip to Italy - with a label that specifies I need to use the contents within 5 days of opening, and this seems impossible. Is it?
I haven't opened it due to that narrow window, but the fish sauce comparison makes me think it would take a lot of food to absorb 5 oz. of colatura without being horrible.