Scripture: Let your conversation be always full of grace, seasoned with salt, so that you may know how to answer everyone. Colossians 4:6 NIV
Observation: Paul closes the letter to the Colossians.
Application: I’ve been a fireman for many years. Since “9-11” much praise has been heaped on me and all firefighters simply because we are firefighters. I write this because, while it’s a noble profession much of the daily life resembles something akin to “boy’s camp” and that isn’t necessarily filled with edifying speech. While it can be fun and entertaining, most of the time the fun ends up being at the expense of one guy or another and the pranks would not be acceptable in most mixed company. To say the least the talk at a fire station isn’t usually something that is “full of grace.” This passage is a good reminder to me to watch what I say so that my words and actions line up as a witness for Christ.
Prayer: Father, help me to curb my tongue and always speak to build up not tear down. I ask this in Jesus’ name. Amen
Doug
Instructions For Life According to Jesus Christ 
Great thoughts Doug. The preceding verse supports you idea that this is talking about our interactions with non-Christians in particular, where we read:
There are very similar exhortations elsewhere in Paul’s letters, e.g: