beadlock rock warrior wheels

I have a 2007 tundra sr5 that I bought used,the first owner did some up up grades to it buy installing hard tonau cover and the beadlock rock warrior wheels.What is the trick for keeping the tire clean from all the brake dust and grime that spins out from under the ring,can spacers be put under the ring so that it drains better?I like the wheels okay,but kinda hard to keep the tire nice and black with all the stuff that gets spun out from under the ring.I have taken the rings off and clean and cleaned the drain slots,and put nylon washers on every other screw,to try to get some extra space for drainage still have same problem gray lines all over the tire from being spun from under the ring.Any thoughts thanks