So given the outbreak of severe lung disease apparently related to vaping, mentioned in recent Tildes threads here, here, and here, I thought I'd provide some semi-informed opinion and experience.

I've had to kick a nasty smoking habit more than a few times, and the last effort was only partially successful. I stayed hooked on nicotine gum, got jaw problems, and switched to vaping.

Vaping was cool! You can play with the electronic gadgets, get involved in the vaping equivalent of hot-rodding and over-clocking communities, play with liquid formulas, build coils, and do all kinds of intricate hobby-type stuff... while slowly poisoning yourself. Vaping was cheap, both by comparison with cigarettes, and with the FDA-approved nicotine-cessation systems. I'd been spending $50/week on gum, but $20/month for the liquids.

I was breathing outrageous dragon clouds, going through 50 ml of liquid a week, and getting nowhere near nicotine freedom. Despite careful avoidance of noticeably irritating flavors, I was getting back to the good old smoker's cough in the morning.

I've since formulated a super-simple homegrown nicotine mint recipe (below) that's as minimally toxic as I can manage, and very slowly gotten down to the equivalent of a cigarette or two a day.

So here's my advice:

1. Avoid pre-made e-liquids and cartridges. There's no telling what's in them; in the U.S., at least, there are no labelling requirements other than nicotine concentration.

2. Avoid flavorings altogether. "Generally Regarded As Safe", the FDA designation for flavorings, only applies to food ingredients. Many common flavor chemicals are known as toxic to inhale. Extracts are often complex mixtures, and there's little data on how all the constituents may interact in your lungs.

I'm not going to provide advice on "safe" ones - just don't use flavorings.

3. If you must vape, do so at the lowest possible temperature. Even unflavored liquids can create toxic byproducts when heated.

You can get pure, unflavored USP-calibrated nicotine liquid base, in a wide range of concentrations, from the same vendors that sell other e-liquid ingredients. I personally preferred propylene glycol (PG) base, because it vaporizes at a lower temperature, and forms less toxic heat decomposition byproducts than glycerin.

4. Don't vape. Nicotine inhalation has some pharmacological advantages - quick brain hit, few or no gastrointestinal effects, but lungs really want clean air. If you're seriously nicotine addicted, you can continue on oral or dermal products with less risk. If you're in a country that doesn't charge outrageously for drugs, there are regulated nicotine nasal sprays.

If you're in a country that does charge outrageously even for over-the-counter medicines, my solution follows.

So, the latest and greatest version, the ultimate plug-and-play version, of the cheap garage DIY nicotine mint:

SAFETY WARNINGS:
Nicotine is a deadly, neurotoxic poison, even on skin contact.
-Do not use nicotine solution concentrations greater than 24 mg/ml at home. Even this concentration is potentially hazardous - wear gloves, work on a washable tray to contain any spills, purchase the smallest size containers you can. Higher concentrations are extremely dangerous without special precautions I won't discuss here.

• Store all nicotine products, treated mints, and potentially contaminated tools and materials far out of the reach of children and pets, preferably under lock and key.

• Wash any exposed skin under running water as soon as possible. Call a Poison Control Center immediately if you suspect that there's been an incident of ingestion or extensive skin contact with nicotine liquid.

• Store mints and materials only in properly labeled, secure containers. [I've found a labelled medicine bottle eliminates social awkwardnesses about not sharing candy.]

• Work on a washable surface, wipe up, wash down with soap and water, and safely dispose cleaning materials for any spills.

• Following these instructions is at your own risk. Based on my knowledge and experience, this nicotine mint recipe is safer than smoking or vaping, but to an unknown degree. You should consult a doctor and/or use approved pharmaceuticals.

Tools and materials:

• Intact 1-qt. (1 L) Ziploc or other sealable polyethylene bag

• 10 ml syringe, optionally with 12- or 14-gauge Luer-lock blunt needle

• Nitrile gloves

• 24 mg/ml (2.4%) nicotine USP solution in propylene glycol** (There are many potential vendors.)

• 8-pack of Altoids "Arctic" flavor sugar-free mints* (cheapest available price on Amazon)

This recipe makes approximately 389 mints at 1.2 mg/mint nicotine strength. Divide or modify it at risk of your own math.

Instructions:

1. Open tins of mints and empty them into the Ziploc bag.

2. Wear gloves. Using the syringe, measure and add 20 ml of nicotine to the bag. (Nicotine solution comes in sealed bottles. To minimize risk of spills, you can use a blunt needle tip on the syringe to pierce the seal and withdraw nicotine liquid without fully opening the bottle.)

3. Completely seal the Ziploc bag. Massage the mints and nicotine liquid together until uniformly distributed and completely coated.

4. Let stand at least overnight, turning and mixing the mints every few hours, until all the liquid is completely absorbed.

Use:

Dosing is similar to nicotine lozenges - hold a treated mint under your tongue until dissolved, repeat no more than a total dosage of 24 per day.

*There are other sugar-free mints that are usable, but I've found sorbitol mints work best for this purpose, and the 0.5 gm per mint size gives a nicely steady nicotine release for 15 - 20 minutes.

**You can use a lower concentration, but the dosage in the final recipe will vary accordingly. Exceeding 20 ml per 8-pack of mints may leave them sticky, and if the liquid isn't fully absorbed, you can become ill from handling the mints. Don't do it.