I recently had the opportunity to use a friend’s induction heater to remove the spark plugs from the engine in my brother’s Dodge van. He had not changed them in over 90,000 miles of use. I removed the easiest of them to access (with the doghouse removed) and it was TIGHT!!! Assuming that penetrating oil wouldn’t get past the plug gasket (and reluctant to further tempt fate), I borrowed the heater and alternated applying heat to the nut of each remaining spark plug and dousing it with a soybean-based penetrating oil my friend also swears by. It worked like a charm. None broke. Though pricey, the induction heater was safer than an oxyacetylene torch and allowed the heat to be applied to the spark plug, only. If I still did this kind of stuff every day, I would definitely own one.