The angel in the house

I have a lot of admiration for people who keep houses clean and tidy. It's not one of my virtues. At the moment, as I start piling up things to get rid of, doing anything in my flat is like one of those slidey puzzle games: I have to move large numbers of things in sequence in order to get at any one particular cupboard. The water here is so hard that even Cillit Bang! (hardcore remix here) won't remove the encrusted limescale on my bath and instead I have to scrape it off flake by painstaking flake with nylon pan scrapers from Lakeland.

I looked on the internet for ways to clean grouting, and someone recommended a mixture of bleach and baking soda. This alarmed me, because it sounds like one of those home-made bomb recipes. And if you put the wrong cleaning products together you can produce chlorine gas -- apparently people do die from mixing toilet cleaners, though I think it has to be bleach and something acidic, which baking soda isn't. I know that baking soda is sodium bicarbonate, and wikipedia tells me that's NaHCO_3. I would consider myself well-educated if I could predict whether that would be a safe thing to mix with chlorine bleach. But I have no idea, and therefore I am not.

Tomorrow my mother is coming up, and because she had a scientific education she may know the answer. But I'm afraid she'll be so annoyed by the messiness of my flat that she'll be in no mood for speculations. Even my dad was shocked at it when he was last here, and this is a man who developed a proper forest floor ecosystem in his study while writing a book on trees by just dropping herbarium specimens when he was done with them. (Eventually my mother passive-aggressively bought him a new carpet for his birthday.)