How to purify vessels if some drops of alcohol fall on them

Firstly: 

The scholars differed as to whether alcohol is impure (najis). The view of most of the scholars is that it is impure and they quoted as evidence the verse in which Allah, may He be exalted, says: “O you who believe! Intoxicants (all kinds of alcoholic drinks), and gambling, and Al‑Ansaab (stone altars for sacrifices to idols etc), and Al‑Azlaam (arrows for seeking luck or decision) are an abomination…” [al-Maa’idah 5:90]. Rijs (“abomination”) is impurity. 

Some scholars favoured the view that alcohol is pure. This has been discussed previously in the answer to question no. 59899. 

Secondly: 

If any impurity falls into a vessel, it should be washed with water so as to remove the impurity. Thus the vessel will become pure and it is permissible for the Muslim to use it and put food and drink in it. 

This is indicated by the following: 

1.

The Prophet (blessings and peace of Allah be upon him) forbade the meat of domesticated donkeys when the Sahaabah had been cooking it in pots, so the Messenger (blessings and peace of Allah be upon him) ordered them to empty out the pots and break them. A man said: O Messenger of Allah, or can we empty them out and wash them? The Messenger (blessings and peace of Allah be upon him) said: “Or that.”

Narrated by al-Bukhaari, 4196; Muslim, 1802. 

Al-Nawawi (may Allah have mercy on him) said: 

This indicates that it is obligatory to wash whatever is touched by impurity, and that an impure vessel is purified by washing it once. As for the initial command of the Prophet (blessings and peace of Allah be upon him) to break them, it is to be understood as meaning that it was based on either a revelation or his personal view (ijtihaad), then it was abrogated and washing was specified, and it is not permissible to break them after that because that is a waste of property. And it indicates that if an impure vessel is washed, there is nothing wrong with using it. End quote. 

2.

Abu Dawood (3839) narrated from Abu Tha‘labah al-Khushani (may Allah be pleased with him) that he asked the Messenger of Allah (blessings and peace of Allah be upon him): We live close to some the people of the Book and they cook pork in their pots and drink wine in their vessels. The Messenger of Allaah (blessings and peace of Allah be upon him) said: “If you can find other vessels, eat and drink from them. If you cannot find anything else, then wash them with water and eat and drink.” 

Classed as saheeh by al-Albaani in Saheeh Sunan Abi Dawood. 

The basic principle with regard to this is: if it is known about the mushrikeen that they cook pork in their pots and drink alcohol from their vessels, then it is not permissible to use them until after they have been washed and cleaned. End quote from ‘Awn al-Ma‘bood. 

This hadeeth indicates that washing vessels to remove the traces of alcohol is sufficient, and there is no need to break them. 

And Allah knows best.