Brought an old pair of Skyway Mag's, not Tuff's which were faded blue. Tried to dye them black with no success, can anyone help. First time attempt. Big plastic tub, hot water, added salt, mixed, added Rit dye powder two of, put in wheels and left for a hour with the odd stir. Took em out and colour hasn't taken too well. Wanted a deep black colour and they've came out darkish blue and a bit patchy. Any ideas or have I just got to repeat the process ?