Is dead skin around the nails considered a barrier that prevents the validity of ablution (wudu) and ritual bathing (ghusl), knowing that it is part of human skin and has not separated from it, and that no human body is free of it?

We only issue fatwas based on what the scholars have decided. Regarding this issue—that is, dead skin (Qashaf)—we have not found any statements from early scholars contradicting what we have mentioned: that it acts as a barrier preventing the validity of ablution, as stated in Bulghat al-Salik. However, it is not necessary to search for this dead skin before ablution; rather, one should act upon the original principle, which is the absence of anything that must be removed, unless its existence is certain. If it is found after prayer and it is probable that it appeared after ablution, then the purification is valid. As for the analogies mentioned, they are not to be relied upon.