Hmmm GB, was this a new carboy when you started your brewing adventure? If so, then I would think that a brush and cleaning solution should do the trick. We use a cleaner/sanitizer called Sani-brew. It is a combo of TSP and chlorine. DH cleans everything with it before brewing and after. Usually he just puts a small amount of the solution he has already made up(this stuff comes as a pink powder) into the carboy, covers the opening with his hand and (maybe a clean cloth to protect your skin)shakes it for a couple of minutes, then rinses well. The odd time he may be required to use the brush.
Sanitizing is key, we keep all of our sanitized equipment in plastic, lidded bins, everything gets cleaned and sanitized before going back into the bin and again before use.
We make both wine and beer, and clean all of our bottles this way, beer bottles get soaked in the solution before cleaning with the sprayer and a sulphite rinse. Since DH is the "Chief Bottle Washer" I could be missing something here, but I will check with him and write an addendum if needed. It's my job to fill, label and