I spray some widex on a paper towel (away from the tank) and clean the outside front.
I have a FOWLR system, never dosed any calcium and have never done a water change. Tank has been setup since April 2007.
I've never cleaned the inside back of the tank. I used to clean the sides (inside) but for the past few months I have not done so diligently only because the coraline has spread like crazy and I kinda like it. The inside front I clean and scrape every week or so.
Brief picture history of coraline growth:
June 2007:
September 2007:
March 2008:
This is 9 months worth of coraline growth. My wife won't let me clean it too much from the corners.....she likes the color and effect