Maybe some soapy water, a little bleach, a soft brush or cloth mounted on an extendable pole. There's nothing wrong if you want to scour clean your sewer hose, but it is not a task my DW or I want to routinely perform. We try to keep the whole dumping process simple and flush out sewer hose by running a full tank of grey water through it followed by a quick rinse if water is readily available. The other thing we do (only when we dump at home) is to hang the sewer hose allowing it to fully drain and dry. We store our sewer hose, hose support, and various attachments in a small rubbermaid tub and don't notice any offending odors in our passthrough basement storage.