What baking soda does not do

Bicarbonate of soda is the most over-promised product in the house. It is genuinely useful for about five jobs and useless for a dozen others it gets recommended for. Here is the honest split.

What it is genuinely good at

• Absorbing smells in a closed space. A fridge, a bin, a pair of trainers. It works because it neutralises acidic odour compounds. Give it days, not minutes.
• Gentle scouring. Burnt pans, oven shelves, a stained mug. It is abrasive enough to shift residue and soft enough not to scratch most surfaces.
• Cutting grease, because grease responds to alkali. A paste on a grill pan, left twenty minutes, saves a lot of scrubbing.
• Softening hard water in a wash, which lets the detergent work properly rather than fighting the limescale first.
• Smothering a small fat fire. Keep some within reach of the hob.

What it will not do

• It does not disinfect. It kills nothing. If the job is germs, bicarb is the wrong product and you need an actual disinfectant.
• It does not unblock a drain on its own. The bicarb-and-vinegar volcano is satisfying and mostly theatre: the two neutralise each other into salty water and carbon dioxide, so you have spent both ingredients to achieve less than a kettle of boiling water would.
• It does not whiten teeth safely as a habit. It is abrasive, and enamel does not grow back.

What it will ruin

• Aluminium. It darkens and corrodes it. Keep bicarb away from aluminium pans and trays.
• Anything gold-plated or softly lacquered, where the abrasion takes the finish straight off.
• Marble, granite and other polished stone, for the same reason.
• Wool and silk. Alkali damages protein fibres, which is also why you keep those away from biological detergent.

The one that matters

If you remember one thing, remember that bicarb and vinegar cancel each other out. Using them together gives you the fizz and then a weak salt solution. Vinegar has its own list, and the two barely overlap. Pick the one that suits the problem you actually have.