The spray on version of Herculiner isn't that bad to clean (in my opinion). I just used a soft bristle brush to clean it and a low gloss tire shine with UV inhibitors.

But Extinct is right - its not really permanent. At some point, depending upon sun, this stuff will degrade. I had durabak on the bumper and it faded and degraded after a year of Florida sun and I had to remove it. At some point I will get the paint professionally done, but can't afford it right now - too much money in this thing already!