Pretreating Fabric: Which way is best?

Vintage hangers available on etsy here I have decided that I will use that fabulous piece of pink and gold designer wool for the skirt I am making. This now presents a new dilemma. How do I pretreat or pre-shrink it? With my black dress, I did the wet towel and dryer thing. More on that technique here. But the difference was that it was wool from a box store that if I ruined I could