Apple - Can I put out a cigarette on aluminum Mac Books?

Yes, your cigarette will be irreparably damaged. You will have to replace it with a new one.

I would say that the only damage caused by a cigarette to the aluminum itself would be cosmetic.

Clearly, the pebbled surface will trap nicotine and ash on the Aluminum. I suspect that Apple anodizes their unibody parts - and if so, that creates a hard, durable layer of aluminum oxide that protects the metal from scratches, stains, and further oxidation

I also expect that action would drive most neat freaks up the proverbial wall, but from a chemical and heat aspect - a single lit cigarette doesn't have enough heat to do any damage. It would slightly warm up a small area of the case but do no harm to the insides. Also, I've seen solid aluminum ashtrays in use for tens of years in harsh environments with no real pitting or permanent damage to them. An internet search for "milled aluminum ashtray" or "milled aluminum engine block" will show that aluminum (and aluminum alloys) can stand up to substantial heat in diverse settings.

I would be more concerned at the smoke, tar, nicotine getting inside the display and the Mac, corroding the circuit boards, covering contacts in ports and clogging the blowers over time.

• Tacky, messy, provoke a reaction in others? - yes
• Damage the aluminum surface? - not so much

The short answer is 'yes,' it will damage the aluminum. The burning cigarette will accelerate the rate of oxidation. Maybe not one cigarette will make a noticeable mark, but given repeated exposure, you would see a difference.