Originally Posted By: scurvy
I prefer to do it with the head slightly warm to the touch. A spritz of penetrating oil at the base of the threads the day before is a good option as well. Also ever so slightly tighten the plug first before turning it out - helps break any corrosion and the plug to turn freely. Use the smallest ratchet reasonable in order to lessen the chance of any side loading.
I've read NGK's treatise on anti-seize, I still say bollocks to that and put a tiny dab of nickel-based anti-seize on all spark & glow plug threads before hand-threading it first and finishing with a 1/4" ratchet by hand. A couple other issues with their tech bulletin - typical 'trivalent Zinc chromate' coating is not a long-lasting corrosion treatment and the amount of anti-seize they show in the second page is a ridiculous amount. I put a tiny dab on a gloved finger and roll it around the threads, only putting the thinnest film possible onto the plug.
Never had one get dorked up with this method and always had them come out easily.
Probably the only reason they state not to use antisieze is because of so many variables at play and they have no control over the amount of antiseize used, even if they were very specific about it. Considering that most people are clueless about these things, but are very quick to sue, it's safer to remove that option all together for the consumer.
Someone actually did dig out a document for Autolite or some other spark plug manufacturer, probably meant for professionals that allowed the use of antisieze.
Just like automakers do not recommend fuel and oil additives. There are so many additives available on the market and so many variables that could negatively impact engine performance and reliability during warranty, that it's simpler to ban their use. Meantime dealers are free to use all sorts of additives without affecting the warranty coverage.
That's the nature of the beast now days. Companies have multiple faces, multiple requirements, multiple stances all aimed at a specific market segment they're trying to cater to.