Milan has a really efficient waste management system, recycling 89% of urban waste in the municipality area.
Please follow rules and ask if not sure where to throw something: fines are really heavy (and they DO check your bin)!
NEUTRAL TRANSPARENT BAG
Unsorted waste
All the refuse that cannot be treated as separate waste
YELLOW BAG
Plastic and metal
Plastic bottles, tubes and bags, plastic and polystyrene tubs for food, metal tins and tubes for food, cans for drinks.
WHITE CONTAINER
Paper
Newspapers, magazines, books, notebooks, cardboard boxes, cardboard packagings, paper drink containers. Only clean paper (pizza box goes into unsorted for example).
BROWN CONTAINER
Food and organic waste
Fruit and vegetables waste, meat, fish, kitchen waste, food leftovers, rice, bread, biscuits, pasta and baked food
GREEN CONTAINER
Glass only
Bottles, jars and vases
Bags color inside the flat may be different, but if you want or need to dispose garbage into the building bins, the colors will always match the one above.
If you need more info have a look here.