Well I lived in Poland last summer and worked as a missionary with university students. I ended up looking at it in this way: Can I expect someone who has no relationship with Christ to act like they do? Is my telling them to not use language around me a form of judgment?
Although I do not agree with being profane I also had to remember my ministry was to these exact people, people who had no reason to 'not' be profane, and so I myself although I did approve of the profane language I never scolded them for it or showed judgment for it...After all, do we expect children to behave before they know how? Similarly I could not expect a non-Christ follower to act like one before they know Christ.
But at the same time there were instances, such as if I happened to have kids and I invited some of my non-Christian friends over, I would politely ask them to avoid profane behavior in front of my children as it is my duty to raise my children under God.
Like Mulehide above me said, out of my life’s testimony it is very seldom my non-Christian friends ever say profane things around me. They know my life and they respect me for it without me having to ask.
So like you asked "How do you deal when it comes to profanity?" I deal with it first through prayer. I pray God will help me to not get angry, and if someone uses God's name in a profane way I will certainly correct them for it, because that is one thing I will not stand for. But I do so lovingly and without judgment. Secondly I remember they are not followers of Christ and it can not be expected of them to act like a Christ-follower. Third, they end up not being profane very often because of Christ in my life and when they are it is usually not intentional.
Hope it helps,
Chris