The validity of prayer is conditional upon the validity of one's purification (wudu or ghusl). A key condition for valid purification is that water must reach all parts of the limbs that are required to be washed.

Shaykh Ibn Baz addressed the issue of substances that form a layer on the skin. If a woman performs wudu while wearing nail polish, her wudu is not valid because the polish prevents water from reaching her nails. Consequently, any prayer she performs with this invalid wudu is also not valid. The same ruling applies to any form of makeup that is waterproof and creates an impermeable barrier on the skin of the face, hands, or arms, as it prevents the water from reaching the skin that must be washed in wudu.

Shaykh Ibn Baz stated: 'If the makeup has a substance (i.e., it forms a tangible layer), it must be removed before wudu so that the water can reach the skin. If it is merely a color and has no substance to it, then the wudu is sound.' Regarding nail polish specifically ('manakir'), he clarified that it must be removed before wudu.

However, if a woman performs wudu correctly, ensuring water reaches all the required parts of her body, and then applies nail polish or makeup, her wudu remains valid. She can pray while wearing them for as long as she maintains her state of purification. Once her wudu is nullified, she must remove the nail polish and any waterproof makeup from the relevant areas before she can perform wudu again for the next prayer.