How can one differentiate between makeup that prevents water from reaching the skin during ablution and that which does not, especially oily and "waterproof" cosmetics, and powder cosmetics?

The water must reach all parts of the ablutionary organ; otherwise, the one performing ablution must repeat their ablution and prayer, by agreement of the four schools of thought. Materials that prevent water from reaching the skin are of two types: materials with a physical mass, such as waxy substances and paints. If these materials are not water-resistant, like some makeup and powder, it suffices to rub the skin well to ensure water penetration. However, if they are water-resistant, they must be removed before ablution. The second type consists of materials that do not have a physical mass, such as oils, creams, and kohl residue. These do not invalidate ablution, but it is preferable to rub the skin to ensure water reaches it.