Not Obliged to Peel off Skin of Cracks on Feet
12-5-2019 | IslamWeb
Question:
Assalamualaykum. I have a question, my feet are a bit cracked and there is some kind of dirt in the crack and this dirt can only be removed by peeling off the skin (i have been doing this frequently), If i am not removing this few dirt is my thaharah valid or not?
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah and that Muhammad 
is His slave and Messenger.
Allah has not ordained you to peel anything from your skin because of the dirt that is on it. If the dirt has a mass that prevents water from reaching the skin, then if it can be removed by washing it or rubbing it, then this is good. However, if it is hard to remove it, then hardship necessitates easiness and Allah does not charge a soul except with that within its capacity.
The jurists stated that ablution is valid with something that is hard to avoid.
Al-Mirdaawi 
from the Hanbali School of jurisprudence, said in al-Insaaf:
"One view is that ablution is valid from a person who finds it hard to avoid the dirt, like those who work in factories, and those who do hard works, such as agriculture and the like. This is the view chosen by the author of the book entitled at-Talkhees. Besides, the author of the book al-Furoo’ considered ablution to be valid (from the people who find it hard to avoid or remove the dirt). The Shaykh (i.e. Ibn Taymiyyah) held that the same ruling applies to any insignificant thing on the body that prevents water from reaching the skin, like blood, dough and the like, and this is the view chosen by him (i.e. by Ibn Taymiyyah).” [End of quote]
The rule established by the scholars is that hardship necessitates easiness and that when the matter is difficult, then it entails to be alleviated.
Allah Says (what means): {…and has not placed upon you in the religion any difficulty..} [Quran 22:78]
Therefore, if the dirt does not prevent water from reaching the skin, or that the dirt is insignificant, like the one under the nail, or it is not possible to remove it, or its removal is of unbearable hardship, then ablution is valid with its presence.
Kash-Shaaf Al-Qinaa', which is one of the books of the Hanbali School of jurisprudence, reads:
“A little dirt under a fingernail does not affect purification (Ghusl or ablution), even if it prevents the water from reaching the skin, as this is quite common, because if ablution was not valid with it [dirt], then the Prophet would have clarified it since it is not permissible to delay a clarification from the time of need for it. Shaykh Ibn Taymiyyah also considered that any insignificant substance on the body, regardless of which part of the body it is on, that prevents water from reaching the skin, like blood, dough or the like, takes the same ruling. This is the view chosen by him (Ibn Taymiyyah) based on analogy with the little dirt under the fingernail. The expression of the book al-Muntaha ‘and anything else under the fingernails and similar things’, applies to the cracks on some body parts.” [End of quote]
For more benefit, please refer to Fataawa 358009, 364156, 361111, 278056, and 357280.
Allah knows best.