1. It is Mustahabb for the slaughterer to sharpen his knife.
2. It is Makruh to let the knife reach the spine or to cut off the head. The Zabihah may nevertheless be eaten.
3.It is Mustahabb to make Nahr of the camel [spearing the throat]. If slaughtered it is permissible but Makruh. It is Mustahabb to slaughter of sheep and cattle. If Nahr is made it is permissible but Makruh.
4. If an animal which cannot be eaten is slaughtered according to Shari'ah, its hide and flesh is clean, even if it cannot be eaten. The skin of humans and pigs will however not be regarded as pure because tanning and slaughter do not have effect upon them.

~ al-Quduri ~