All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Drinking alcohol is prohibited and it is among the grave sins. The person who drinks alcohol should be given advice and reminded about Allaah so that he may repent of such a grave sin. For more benefit, please refer to Fataawa 81567 and 86752.
Alcohol is impure according to the vast majority of Muslim scholars. If alcohol touches any vessel or any other object, it renders it impure. However, if the person who drinks alcohol merely touches a vessel or anything else, they do not become impure unless it is known (for sure) that they have come in contact with alcohol. When the person gargles (or rinses his mouth) with water after drinking alcohol and it alters the water's smell, taste, or color, then this water is considered impure and whatever comes in contact with this water becomes impure as well. However, if the impurity (i.e. alcohol) does not alter the water’s smell, taste, or color, then the water remains pure and does not make any object impure.
In any case, you should beware of satanic whisperings; nothing is regarded impure, whether vessels or any other object, unless it is proven or known with certainty that it has come in contact with alcohol.
Allaah Knows best.