Drinking non-wine beverages: It is permitted on temporary occasion to drink any non-wine beverage from a vessel of a Gentile even if the vessel was designated for drinking or storing wine, so long as the vessel is properly rinsed from any leftover wine prior to usage. If one desires to use the vessel on a permanent basis, then it is required to be rinsed well three times prior to its use even for use of non-wine beverages.
Drinking wine: It is forbidden to drink wine from a glass vessel of a Gentile that was used to drink or store wine, until it is rinsed well three times.
May I have a glass of water, or other non-wine beverage, from a wine goblet in a non-kosher restaurant or home of a Gentile?
Yes, after making sure that it is rinsed well for any leftover wine.
May I have a glass of kosher wine from a wine glass in a non-kosher restaurant or home of a Gentile?
Yes, but only after you rinse it out well three times with water.
What do I do if I purchased or received used wine glasses from a Gentile and would like to now use it?
You are to rinse it out well three times and may then use it as you wish.
What is a kosher restaurant to do regarding serving glasses of wine to a Gentile customer?
The restaurant should either only serve Mevushal wine, or make sure to rinse the glass cup three times after the Gentile drinks from it.
A Gentile guest drunk non-Mevushal wine from my non-disposable cup. What I do with the cup now?
Simply rinse it well three times and then return it to its regular use.