Some materials exhibit novel transport phenomena when they are made very thin. We use a focused ion beam (FIB) of Ga²⁺ ions to precisely remove small sections from single crystals of various materials and polish them to sub-micron thicknesses (FIB microscope located at the Princeton Imaging and Analysis Center.) These thin crystals have a large surface-to-volume ratio which can enhance transport effects from surface states that are normally obscured by bulk states. For example, in a recent paper we found that thin lamellae of the ferromagnetic Weyl semimetal Co₂MnGa host an unexpected conductance anisotropy that rotates by 90 degrees between the upper and lower faces. Using a series of careful measurements at temperatures down to 1.8 K, we show that this highly unusual transport anisotropy most likely arises from distinct topological surface states.