If your milk 
goes a bit past where you like to drink it, consider making pudding.
It’s hard to find organic whole milk in half gallon plastic or glass so I normally buy a gallon and do something with the extra if we have any.
Just a reminder that milk and juice cartons are plastic-coated paper and go in the trash.
All the containers shown above are easily recycled in curbside carts. To be nit-picky, the liner/seal on these containers are mixed-materials and need trashed. Sugar and cocoa can occasionally be found in bulk bins, I’m not sure about cornstarch. Argo is the only cornstarch available in plastic at my grocery, otherwise cornstarch comes in the plastic and metal-lined paper canisters, which is also the reason we have Trader’s Joe’s cocoa. Cocoa usually comes in those same composite/mixed-materials canisters and those have to be trashed. You can recycle the metal cocoa lids. I will share that in my husband’s opinion, Trader Joe’s cocoa is not as tasty for his drink mixes as other brands that come in non-recyclable canisters, but if you need it just for baking it’s good.
I use the pudding recipe in the More-With-Less Cookbook.
It uses two cups of milk. You’ll see that the subtitle on the cookbook says, “consume less… resources” which is why I bought it. I’m enjoying the recipes so far. 
I bought it used 
so it’s an older version that uses margarine so I just modify that bit for butter, or coconut or olive oil.
Newer versions update the recipes.
