Lets start with the basics.
All Christians either "do" or "should" know not to use the Lord's name in vain. Even some non-Christians know and believe this. What do I mean? I'll initialize.. (G.D.). That's as far as I'm willing to go there. Here's scripture.
Exodus 20:7 7 "You shall not misuse the name of the LORD your God, for the LORD will not hold anyone guiltless who misuses his name.
The following verse, to me, means that a Christian should not use any type of profanity whatsoever.
Isaiah 32:6 6 For the fool speaks folly, his mind is busy with evil: He practices ungodliness and spreads error concerning the LORD; the hungry he leaves empty and from the thirsty he withholds water.
Okay. So what about words that are in the Bible? For example; Hell, damn, ass, fool, etc...
Hell is obviously a place (a terrible place at that). In the sense of speaking of a place, I think its fine to use. But one should never condemn someone verbally to this place. As Christians, we should not feel hate in hearts. However, even if you did, you could not hate anything/anyone strong enough to cast it into Hell. Therefore, we should never ever use this word in this manner.
Damn means: Sentence or condemnation to everlasting punishment in the future state; or the state of eternal torments. As I've stated earlier, one should never feel this way about anything/anyone, therefore never have a reason to even use this word period.
Ass is a word used to describe a donkey. If you're not seriously talking about a donkey, this word is inappropriate. Stick to proper words and for this word's sake... just say "donkey" so others won't get the wrong image of you.
Just remember Isaiah 32:6 from above.
Just a little extra something to think about below.
We are also instructed not to swear (I believe promises are different than swearing). Does this mean in court, we should not "swear?" Here's the verse:
James 5:12 12 Above all, my brothers, do not swear—not by heaven or by earth or by anything else. Let your "Yes" be yes, and your "No," no, or you will be condemned.