First wet it down with the big car wash brush and soapy water. Then scrub it with a scrubby and Soft Scrub. Then more soap and water on the brush. Then rinse well. Two feet at a time. And when it was all done, go back and wash down the gray sides to make sure none of the soft scrub dripped down on it.
And while this wasn't actually time to smell roses since I don't HAVE any roses, I did spot this pretty butterfly/moth. She was enjoying the mist from my hose and then sat around in the sun drying out her wings. She must have needed a shower!