"A sheep died so the Messenger of Allah ﷺ said to its owners: 'Why dont you remove its skin, then tan it so you can have something useful from it."  

رَسُولُ اللَّهِ ﷺ لأَهْلِهَا أَلاَ نَزَعْتُمْ جِلْدَهَا ثُمَّ دَبَغْتُمُوهُ فَاسْتَمْتَعْتُمْ بِهِ  

That the Messenger of Allah ﷺ said: "Any skin tanned, then it has been made pure." This Hadith is Hasan Sahih. This is acted upon according to most of the people of knowledge, they say that when the skin of a dead animal has been tanned then it has been made pure.  

رَسُولُ اللَّهِ ﷺ أَيُّمَا إِهَابٍ دُبِغَ فَقَدْ طَهُرَ هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ وَالْعَمَلُ عَلَى هَذَا عِنْدَ أَكْثَرِ أَهْلِ الْعِلْمِ قَالُوا فِي جُلُودِ الْمَيْتَةِ إِذَا دُبِغَتْ فَقَدْ طَهُرَتْ  

"A letter came from the Messenger of Allah ﷺ saying: 'Do not use the skins of dead animals, nor tendons.'"  

أَتَانَا كِتَابُ رَسُولِ اللَّهِ ﷺ أَنْ لاَ تَنْتَفِعُوا مِنَ الْمَيْتَةِ بِإِهَابٍ وَلاَ عَصَبٍ