You just mentioned milk shake. I have found that milk (and some other dairy products) increase my mucous problems. I still drink protein smoothies, with fresh fruit whey protein powder sometimes with yogurt, and now made with Vanilla flavored soy milk. At first I didn't like this stuff, but now I have it in my cereal coffee, and anywhere I would have used milk. There are a lot of brands out there, some a genuinely nasty or just watery. The one that I found I liked is called Silk. Plain flavor... well that name says it all, but the vanilla one has become one of my staples.