There are many good suggestions: Things I have used include assorted rag mops and a "Van Wash" brush, this is a generic brush from an auto parts store, though I have never used this feature it has a "Flow through" design so you can hook a garden hose to it (I may do it that way next time).
The handle is an "extension" type, fully extended it is a full length mop handle, I like it way better than a mop.
One brush I have not tried that I would like to is a FULLER BRUSH Company window washer's brush. But frankly I do not see it as being an improvement over the van-wash brush.
Home is where I park it!