It is Islamically commendable to give care to personal cleanliness, as Allah likes those who purify themselves. He (glory be to Him) said, “Truly Allah loveth those who turn unto Him, and loves those who have a care for cleanness.” (Al-Baqarah 222) Muslim reported on the authority of ‘Abdullah ibn Mas`ud who narrated that the Prophet (peace and blessings of Allah be upon him) said: “No one who has an atom’s weight of pride in his heart will enter Paradise.” A man said, “What if a man likes his clothes to look good and his shoes to look good?” He said, “Allah is beautiful and loves beauty. Pride means denying the truth and looking down on people.” (Sahih Muslim)

However, a Muslim should look for pure substances to use them. If such substances include impure ingredients such as pig fat and the like, they are impure and, consequently, unusable for us as Muslim. We all know that Allah has prohibited the flesh of pig in the Qur’an, Allah the Almighty says, “Forbidden unto you (for food) are carrion and blood and swine flesh” (Al-Ma’idah 3) Also, it is reported that the Prophet (peace be upon him) was asked about Khamr (intoxicants) as it is used for medication. He answered, “It is not a cure, it is a disease. Allah does not put your cure for my Ummah (nation) in that which He has been forbidden for them.” (Related by Al-Tirmidhy and Al-Daraqutni)

There is disagreement among scholars concerning the purity of transformed substances that were impure at first. Hanafis, Shafi`is and Ahmed (in a report from him) are of the opinion that things becomes pure if they are completely transformed to a pure state. They based their ruling on that the impurity has been removed and there are no effect to it; consequently such materials become pure and usable. Also, they draw Qiyas (analogy) between this case and the case of musk; it is blood but it becomes pure because all the characteristics of blood in it have been changed. There is another opinion attributed to Ahmad in another report from him, a saying of Malik and a saying of Al-Shaf`y where they maintained that impurity continues in spite of transformation. However, the first opinion is stronger and preferable. Accordingly, if the prohibited element in such substances has been totally transformed and the impurity is removed, then it becomes pure and usable.