Here's what you need to know: Pre shave oil isn’t a replacement for taking a shower or wetting your face prior to shaving. You should still apply warm water or take a shower prior to shaving to ensure the closest and most comfortable shave. Pre shave should be applied before any shaving cream or soap touch your face. In addition to being incorporated into the pre shave routine, pre shave oil is often widely used in the post shave process as well.