Is it okay to boil milk (making steel cut oats) I am trying to make simple oatmeal (steel cut), and on the package the directions say to boil milk, add the oats, then simmer for 25 minutes. But the milk is starting to get a film on top and is becoming a cheese-like consistency which doesn't look too appetizing in my oatmeal. Up until now I've always boiled oats in water and added cold milk after. Is this desirable?

I should add that the milk is actually a bit old and while past the expiration date, still smells okay and has not spoiled yet. This is also my first time making steel cut oats but I doubt that makes a difference.
Yes, it's fine to boil milk - or at least to simmer it. Milk gets really foamy when it boils, and tends to boil over, so you probably don't want to actually boil it, but rather quickly turn the heat down when it shows signs of boiling, and let it simmer. It does develop a film on top sometimes, but nothing that can't just be stirred in and dissolved, and you should be stirring your oats reasonably frequently anyway so they don't stick to the bottom.