Is Wudu Valid with Nail Polish on?
Question

A woman was away from the city, and did not know that the nail polish must be removed to make Wudu and pray. When she knew that she must remove it, she tried to find a nail varnish remover to use but she could not find it. She could not go to the city to buy it either. She was making ablution and praying with it on for one week. What is the ruling on this?
Praise be to Allah.One of the conditions of ritual purification being valid is that the water must touch the skin. If there is any barrier such as grease, paint, wax or glue that prevents water reaching the skin, then the purification is not valid and prayers offered in that case are not valid. 
The evidence for that is the words of the Prophet (peace and blessings of Allah be upon him) to Abu Dharr (may Allah be pleased with him): “If you find water, then let it touch your skin, for that is good.” (Narrated by Abu Dawud, 332; classed as authentic by Al-Albani in Sahih Abi Dawud) 
Imam Ash-Shafi`i (may Allah have mercy on him) said: 
“If there is any mastic or anything thick on him that will prevent the water from reaching the skin, his washing of that part for Wudu is not valid, unless he removes it or removes enough so that he knows that there is no barrier to the water touching the skin.” (Al-Umm, 1/44) 
An-Nawawi (may Allah have mercy on him) said: 
“If there is wax, dough, henna and the like on one of his limbs, which prevents water from reaching any part of it, then his purification is not valid, whether the amount is large or small. If there are traces of henna and its colour left on the hand, without there being any solid material left, or elsewhere, or traces of liquid grease whereby water flows over the limb but does not stay there, his purification is valid.” (Al-Majmu`, 1/529) 
It says in Fatawa Al-Lajnah Ad-Da’imah (5/218): 
“If the colour is impermeable , then Wudu is not valid unless it is removed before doing Wudu. If it is not impermeable , then Wudu is valid, as is the case with henna.”
Hence this woman should have tried to find something to remove this nail polish , even if she had to go far away to find a place that sold it. She could also have removed it by using a strong kitchen cleaning agent or by rubbing it with a cloth dampened with liquid fuel, and so on.  
We do not think that this woman has any excuse for praying with Wudu that was invalid because of this nail polish. Ignorance may mean that she is free of sin but it does not make the prayer valid . 
She has to repeat the prayers that she offered with Wudu that was invalid because of this nail polish . 
For more details, please see the following answer: 292730 .
And Allah knows best.