Not sure I like the idea of dish soap. It is an abrasive and over the long haul I think it could damage to the finish, clear coat, and decals. I find just using black streak remover when I wash the camper works fine. Spay it on, then wash the camper using car wash soap, doing an area at a time. Then to protect the finish I just use a quick spray and wipe Automotive wax. I also have found that when you have light black streaks, the spay and wipe wax takes them right off. I usually do the waxing while we are at the campground. I do it over a couple of days.