Praise be to Allaah.
Animals are of two types: those whose meat may be eaten and those whoseeat may not be eaten.
With regard to animals whose meat may be eaten if they are slaughtered in the shari manner, their skins are taahir (pure) according to scholarly consensus, even if they are not tanned.
With regard to animals whose meat may not be eaten, they are divided into two categories: those which are najis (impure) when alive, and those which are taahir.
Those that are najis in and of themselves are pigs, according to consensus, and dogs according to the Shaafais and Hanbalis, so slaughtering them (in the shari manner) does not make their skins taahir.
With regard to those that are not najis in and of themselves although their meat may not be eaten, the fuqaha' differed as to whether their skins become taahir if they are slaughtered (in the shari manner). The Shaafais and Hanbalis are of the view that they do not become taahir through slaughter. The evidence quoted by these scholars is that the Messenger of Allah (blessings and peace of Allah be upon him) forbade sitting on the skins of wild animals and riding on tiger skins. This is general in meaning and applies to that which is slaughtered (in the shari manner) and that which is not. Because slaughtering it (in the shari manner) does not make the meat taahir, it does not make the skin taahir either.
The Hanafis and Maalikis are of the view that the skins become pure if the animal is slaughtered in the shari manner. They quoted as evidence the words of the Messenger of Allah (blessings and peace of Allah be upon him): The tanning of leather is its slaughter. And because slaughter (in the shari manner) has the same effect as tanning in removing moist impurities. With regard to the prohibition on sitting on the skins of wild animals and riding on tiger skins, that is because these things are used by people who show off, or because they used to use them without tanning them.
Al-Mawsooah al-Fiqhiyyah, 7/95-96
The more correct view is that the skins of animals whose meat cannot be eaten is not taahir, whether it is tanned or not, because najis skins cannot be purified by means of tanning.
Shaykh Ibn Uthaymeen (may Allah have mercy on him) said:
Animal skins are of three types:
1. Those that are taahir, whether they are tanned or not. This includes the skins of animals that are slaughtered (in the shari manner) if they may be eaten.
2. Skins that are not taahir whether after tanning or before tanning. They are najis. This is the skins of animals whose meat may not be eaten, such as pigs.
3. Skins that become taahir after tanning and are not taahir before that. These are the skins of animals whose meat may be eaten, if they died without being slaughtered (in the shari manner). End quote.
Liqa' al-Baab al-Maftooh, 52/39
See also the answer to questions no. 1695 and 144270
The majority of scholars are of the view that it is haraam to eat snakes.
An-Nawawi (may Allah have mercy on him) said in al-Majmoo, 9/16-17:
The opinions of the scholars concerning the vermin of the earth such as snakes, scorpions, dung beetles, cockroaches, mice and so on is that they are haraam. This is the view of Abu Haneefah, Ahmad and Dawood. Maalik said: they are halaal. End quote.
It says in al-Mawsooah al-Fiqhiyyah (11/233):
The Hanafis, Shaafais and Hanbalis say that snake meat is haraam. End quote.
See also the answer to question no. 138842.
Based on the above:
The skins of snakes are not taahir, even if they are tanned, because they are animals whose meat may not be eaten. So it is not permissible to wear anything made of their skin, whether it is shoes, khufoof (leather slippers) or anything else.
And Allah, may He be exalted, knows best.