1. "
29 No longer allow any corrupt word to leave your mouth..."
The present imperative indicates an on-going action and the negative command is commanding an ongoing action to stop. The aorist imperative would indicate an action beginning to happen and the negative command would be commanding the action not to even start. So, Paul has in mind here that corrupt thoughts arise in the heart and out of the heart the mouth speaks. As the heart is generating the words and sending them to the tongue and lips, this procedure must be arrested before the words leave the mouth. As the psalmist said, "Lord, set a guard on my lips..."
Psa 141:3
2.
"but if there is something good for useful edification let that come forth, in order that it might give grace to those listening. "
In the phrase "edification of use (noun + genitive)" the genitive noun is being adjectivally, and this structure is a hebraic way of saying "useful edification (noun + adjective)". We see this in phrases like "the God of glory" , meaning "the glorious God." The saint's spirit acts as gatekeeper for the words about to leave the mouth. If the word tastes good to the spirit, it is allowed to pass. If it tastes corrupt/impure to the spirit, the word is held in and the sentence is interrupted.
3
. "30 And stop grieving God's Holy Spirit, by which you were sealed for a day of redemption. "
Again, the present imperative commands a present ongoing action to cease. Paul is addressing those who are still saying things that are impure and destructive, instructing them to be more discerning and disciplines in their choice of words.
4.
"31 Let all bitterness, rage, retaliation, rioting and slander be weeded out , with everything evil."
The aorist passive imperative ἀρθήτω commands something to start being done. There are people in Paul's audience who, he assumes, are leaving bitterness, rage, retaliation, rioting and slander to keep on growing in their hearts. He is commanding them to start to pull up those weeds. This list is not exhaustive, so Paul adds "with everything evil" to comprehensively cover whatever he did not include in his list.
5.
"32 And become helpful toward one another,"
The word for kindness (chrEstos) derives from a root meaning "to furnish what is needed". It is not merely a feeling, but helpfulness. Paul is enjoining the saints to meet one another's real needs. ἀλλήλους is a word describing mutual exchange between two or more persons.
6.
"tender-hearted..."
εὔσπλαγχνοι Literally, good-spleened. The bowels being considered are the seat of the emotions. It means compassionate, sympathetic.
7. "
showing grace to yourselves, just as God by means of Christ showed grace to you. "
Paul does not use ἀλλήλοiς (one another) here, but ἑαυτοῖς (themselves). He is not enjoining grace-giving to others but to oneself. A lot of Christians' negative and offensive behaviours come from self-hatred and shame over not being and performing well enough. Giving myself grace, including forgiving myself, speaking encouragingly to my soul, treating my body well will allow me to be more gracious, patient and kind with others.