One important preparatory step I left out.
You'll want to be sure the hose is clear of all debris from end to end. On those really stiff crunchy hoses where the inner rubber cloth layer has hardened, frequently there are strips of the cloth that have delaminated and stand away from the hose walls & wire coil.
I have two bottle brushes, one is stiff bristles and the other is brass wire bristles (I use them in several sizes to clean out organ pipes). The nylon brush is fine for most hoses but if the hose is really delaminating the wire brush really reams it clean of clog potential. The goal is to remove loose bits and accumulated dirt & dust, not strip it down to the wire coil. 
Got an 8 foot 3/8" steel rod from home depot and attached a drill chuck to one end. This holds the brush. The other end I put in the electric drill. However you manage to attach or bolt the brush to the rod...BE SURE THE DRILL IS TURNING IN THE SAME DIRECTION AS THE METAL TWIST OF THE BRUSH BRISTLES.
On the basement floor or outside in the laneway, lay the hose out straight, have a friend (or a heavy vise) hold the hose and run the brush up & down the full hose length a few times. You'll be amazed at what's caked along the hose walls.
Now blow it all out with your trusty vac and carry on.
