hi all, some what noob here, i own a porter cable and jet black m3 that i am working on. so far i've done half of the car and very happy with the outcome... moving on to the back of the car soon which has 4-5 parking sensors, at this point im not sure if i should polish up the parking sensors, or should i tape them up? 1 of the parking sensor looks discolored, i think maybe hand polish this sensor up and it shall match up like the other sensors... what do you guys think? is it safe to polish the parking sensor?