Can cosmetics and household cleaning products be used after the expiration date? And what happens to the substances after this period?

Look at the composition. Cosmetics contain fragrances, they give them a smell. These fragrances deteriorate, which can cause allergies, redness, and other effects on the skin. The same goes for minerals, organic matter.

Many household chemicals can be used, since they practically do not deteriorate during long-term storage. With cosmetics, it is worse, it has a complex composition and contains many organic substances that are destroyed over time or some chemical reactions begin to occur in them.

For example, glass detergents containing ammonia (ammonium hydroxide ) can deteriorate because the volatile ammonia evaporates and the agent loses its effectiveness. Hydrogen peroxide products also deteriorate because hydrogen peroxide is an unstable substance that turns into water over time. Some types of household chemicals are hygroscopic, that is, they absorb water and react with it. And some remain virtually unchanged, especially when stored securely and appropriately.