Get a long handled brush and a squeegee.
https://www.walmart.com/ip/Flow-Thru...eegee/23752087
I simply use a bucket of water, no soap, no hose. I dunk the brush in the bucket and wash. Then squeegee the sides and then a quick wipe with a towel. Even works pretty good for bugs on the front cap. Sometimes the cap needs a bit of a scrub with a pad but most times the brush does the trick.
The no wash rule is usually there to keep folks from using too much water and creating a mess. Never had any one say anything about a quick "touch up" using only a bucket of water