White vinegar is the other half of household cleaning folklore, and like bicarbonate of soda it is brilliant at a few things and quietly destructive at others. The difference is that vinegar's mistakes tend to be expensive and permanent.
What it is genuinely good at
- Limescale. The job it was born for. Kettles, shower heads, taps, the inside of a
washing machine. Acid dissolves the carbonate, and nothing else in the cupboard does it as cheaply.
- Glass and mirrors, diluted, because it evaporates without leaving the film detergent
does.
- Softening laundry, in the rinse drawer. It strips the detergent residue that makes
towels stiff and stops them absorbing.
- Knocking back weeds in paving joints, at full strength on a dry day. It burns the
foliage but not the root, so it is a trim rather than a cure.
What it will ruin, which is the important list
- Natural stone. Marble, limestone, travertine and many composite worktops. The acid
etches the surface permanently and polishing does not bring it back. This is the most common and most costly vinegar mistake in a modern kitchen.
- Grout, which it softens and erodes with repeated use.
- Cast iron and carbon steel, by stripping the seasoning and rusting what is underneath.
- Waxed or oiled wood, where it cuts through the finish rather than cleaning it.
- Rubber seals, including the door gasket on a washing machine, which perish.
Never mix it with bleach
Vinegar plus any chlorine bleach releases chlorine gas. That is not a folk warning, it is ordinary chemistry, and it happens at kitchen concentrations in an unventilated room. The same applies to bleach with ammonia, and bleach with most limescale removers, which are acids under a friendlier name. The full list is on household chemicals.
The rule that saves you money
Acid for mineral problems, alkali for grease and smells. Limescale, hard water and soap scum are vinegar's territory. Baked-on grease and stale odours belong to bicarb. Reaching for both at once usually means the problem has not been identified yet.