Hi Bobbi, Corn silk works great in soap! Use it in a tea like other herbs and use that tea for the lye solution.
I make a sunflower & corn silk soap – the recipe is in my print book (Simple & Natural Soapmaking), but all you have to do is make a tea of sunflower petals and corn silk and use it in your favorite soap recipe.
I also add 1/2 tsp annatto seed powder to the hot lye solution, to give the soap a pretty yellow color. (Strain the lye solution to minimize speckles.)