Why sprinkle salt on a washing-up sponge at night?

Sprinkling salt over a washing-up sponge at night is an old household tip for reducing moisture, unpleasant smells and the feeling that grime has built up. Salt can help the sponge become drier, but it is not a replacement for regular replacement.

Why does salt help to care for a washing-up sponge?

After it has been used, a sponge can remain damp for hours, holding food particles, grease and water. This setting encourages unpleasant odours and the growth of micro-organisms, particularly when the item is left wet on the sink overnight.

Sodium chloride, the main ingredient in table salt, is also known for its role in preserving food. When used on a sponge, its household benefit is drawing out some of the moisture and making the proliferation encouraged by a wet environment more difficult.

This tip is recommended for the following reasons:

• Moisture: salt helps to reduce the water retained inside the sponge.
• Unpleasant smell: lower moisture levels lessen the odour of a stuffy sponge.
• Durability: overnight care can help preserve the utensil for longer.
• Routine: applying it at night gives the sponge more time to dry thoroughly.
• Limitation: salt does not turn an old sponge into a hygienically clean one.

How should you sprinkle salt on a washing-up sponge?

Once you have finished washing up, rinse the sponge thoroughly to remove suds, grease and food debris. Then squeeze out as much water as possible and sprinkle one teaspoon of salt over the damp area of its surface.

Leave the sponge somewhere well ventilated, ideally on a draining holder, without direct contact with standing water. In the morning, rinse it before using it again, removing the accumulated salt and any loose residue left from the night.

Why does the hygroscopic property matter?

Salt is hygroscopic, meaning that it can attract moisture from the air and from the surface on which it is applied. On a washing-up sponge, this helps decrease retained water, making the utensil less likely to develop an unpleasant smell.

A less damp sponge in the morning

The trick works best when combined with ventilation.

Sprinkling salt on the sponge and then leaving it enclosed greatly reduces the effect.

The ideal sequence is to rinse it, squeeze it, add salt and place it on a dry holder.

This effect does not eliminate every micro-organism, but it creates conditions that are less favourable for them to multiply quickly. For that reason, the method is useful for maintenance rather than as a substitute for cleaning, drying and periodic disposal.

To avoid waste, follow this order:

• Rinse the sponge after you have finished washing up.
• Squeeze it firmly to remove excess water.
• Sprinkle one teaspoon of salt over the sponge.
• Leave it on a draining holder overnight.
• Rinse it in the morning before using it again.

How does salt compare with boiling and the microwave?

Boiling is more intensive than using salt, but it requires care around hot water and may distort certain sponges. The microwave is often mentioned as a quick method, but for safety it should only be used with a damp sponge that has no metal parts.

Salt is easier and gentler because it does not rely on heat, need a pan or disrupt a daily routine. On the other hand, it is less powerful than heat-based methods and will not solve the problem of a sponge that is already dark, torn or has a persistent odour.

In practical terms, consider the following:

• Salt: helps the sponge dry and reduces smell, but does not sterilise it.
• Boiling: cleans more effectively, but requires attention to prevent burns.
• Microwave: may reduce micro-organisms, but needs a damp sponge with no metal.
• Regular replacement: remains the safest measure for worn-out sponges.

When should a washing-up sponge be replaced even if you use salt?

As with the warning that a washing-up sponge can collect grime, the salt trick should not become an excuse to keep using the same utensil for too long. A sponge with a strong smell, slime or tears should be removed from the kitchen without delay.

The best habit is to combine careful rinsing, drying in a ventilated area, occasional salt at night and frequent replacement. This helps the sponge last better, smell less and avoid compromising the hygiene of the washing-up, sink and household routine.