I always did it with my fingers to save my gloves. Also so I knew what was on there and what cuts the tire had and if a thorn or glass was still there. (That info was important when I rode sew-ups exclusively, I was an amateur bike racer buying his own tires and I healed fast.)

My "rule of thumb" for wiping the rear tire of my very short chainstayed, steep seattubed racing bike was to find the seatstay and reach down just in front of it. (Nowhere near enough clearance behind the seattube!)

Ben