Bismillahi Al-Rahmani Al-Rahim
If a slaughtered animal's meat is lawful to eat, then tanning its leather
will make it pure. This holds true whether a Muslim slaughtered the animal
according to Islamic law, or it someone from the People of the Book
doing it according to their law.
If an animal is not slaughtered or its meat is unlawful to eat, then
tanning will not make its leather pure. This leather, however, can be used
with things that are dry and solid but not with wets and liquids.
I asked two sheikhs about the problem of leather goods in the West. Both
said that if the leather originates from a country whose population is
considered Muslim or People of the Book, then it is considered ritually
pure. Both sheikhs said that the consumer is not burdened with doing
anything other than looking at the label. Neither sheikh saw any problem in
using wearing leather shoes made of questionable leather since they would
be removed for prayer.