I used Oxy Clean Max on the outside canvas. The black in Fl is often a bit of not only dust and dirt, but pollen. I'm not a big fan of pressure washing for fear it would mess with water-resistance. Also, if you can see pinholes of sunlight from inside the bunk, you can patch with opaque or white candles. You need two. One person inside the bunk presses the base of the candle against the hole, another person outside rubs the base a little against the inside candle and it patches the pinhole with wax!