This chapter mostly stresses the importance of removing impurities. These mostly come in the form of temptation to let yourself go a bit too much. Don’t give in to them! How this is done, that differs between each Buddhist practice, but it’s mostly reflection and observation of mind-phenomena (as usual, if you’ve been reading this series you should begin to see a pattern here).
235. Like a withered leaf are you now; death’s messengers await you. You stand on the eve of your departure, yet you have made no provision for your journey!
236. Make an island for yourself! Strive hard and become wise! Rid of impurities and cleansed of stain, you shall enter the celestial abode of the Noble Ones.
237. Your life has come to an end now; You are setting forth into the presence of Yama, the king of death. No resting place is there for you on the way, yet you have made no provision for the journey!
At the moment of your death, death-god Yama (who looks kick-ass with his swollen face and skull-crown, by the way, grarrrrgh) takes you, and lo, you don’t have anything. You’re not prepared! You didn’t do the right things, you never reflected, you were sloppy, you have no provisions! Feel silly now, eh?
238. Make an island unto yourself! Strive hard and become wise! Rid of impurities and cleansed of stain, you shall not come again to birth and decay.
You can escape the wheel of Samsara, and this tiny concise sentence basically tells you all you need to know about how that’s done. Too bad the real challenge lies in the doing.
239. One by one, little by little, moment by moment, a wise man should remove his own impurities, as a smith removes his dross from silver.
240. Just as rust arising from iron eats away the base from which it arises, even so, their own deeds lead transgressors to states of woe.
The latter at least can be observed first-hand. The impurities are at the heart of what causes this rust, and the rust eats away at you. If you remove the source of it, you will be better off. Remove the source of your anger, your impatience, your greed and your intolerance. That way, their negative effects cannot manifest themselves.
241. Non-repetition is the bane of scriptures; neglect is the bane of a home; slovenliness is the bane of personal appearance, and heedlessness is the bane of a guard.
The guard they mean here is really a guard, a person you hire to guard your house.
242. Unchastity is the taint in a woman; niggardliness is the taint in a giver. Taints, indeed, are all evil things, both in this world and the next.
Hmm, okay, now this one seems a bit mixed up to me. Thanissaro Bhikku, to the rescue! It’s alternative translation time:
In a woman, misconduct is an impurity. In a donor, stinginess. Evil deeds are the real impurities in this world & the next.
Oh. Okay. That’s slightly better.
243. A worse taint than these is ignorance, the worst of all taints. Destroy this one taint and become taintless, O monks!
Not just ignorance in general, but specifically also ignorance about the truth of suffering, the causes of suffering and the path to the cessation of suffering.
244. Easy is life for the shameless one who is impudent as a crow, is backbiting and forward, arrogant and corrupt.
245. Difficult is life for the modest one who always seeks purity, is detached and unassuming, clean in life, and discerning.
Yeah, ever wondered why that is so? The next few verses at least offer some sort of consolation.
246-247. One who destroys life, utters lies, takes what is not given, goes to another man’s wife, and is addicted to intoxicating drinks — such a man digs up his own root even in this world.
248. Know this, O good man: evil things are difficult to control. Let not greed and wickedness drag you to protracted misery.
I like the simile of “digging up one’s own root”.
249. People give according to their faith or regard. If one becomes discontented with the food and drink given by others, one does not attain meditative absorption, either by day or by night.
250. But he in who this (discontent) is fully destroyed, uprooted and extinct, he attains absorption, both by day and by night.
You can take this even further if you like. You can be content no matter what. In pouring rain or when being forced to wait 20 minutes for the next bus or when the cafeteria ran out of nigger heads again and you have to settle for a tartelette aux cerises. And it’s not about controlling all your emotions, crushing them like a tank. It’s about observing them as they arise and not letting them take hold of you.
251. There is no fire like lust; there is no grip like hatred; there is no net like delusion; there is no river like craving.
These awesome similes again. They had a knack for good images back in the day.
252. Easily seen is the fault of others, but one’s own fault is difficult to see. Like chaff one winnows another’s faults, but hides one’s own, even as a crafty fowler hides behind sham branches.
The crafty fowler! I’m in simile heaven!
253. He who seeks another’s faults, who is ever censorious — his cankers grow. He is far from destruction of the cankers.
254. There is no track in the sky, and no recluse outside (the Buddha’s dispensation). Mankind delights in worldliness, but the Buddhas are free from worldliness. 
255. There is no track in the sky, and no recluse outside (the Buddha’s dispensation). There are no conditioned things that are eternal, and no instability in the Buddhas.
This is a series of articles I’m doing on one of the basic Buddhist texts, the Dhammapada. Read the rest of the articles in this series.