Far less toxic but still powerful is Citristrip, an orange slime that will partially liquefy paint in about 10-15 minutes (less if you work in direct sunlight). Spread with a brush, remove with a putty knife; the paint came off in wet sheets. Concentrated citric acid, so you still want to wear gloves, but makes the truck smell like Orange Crush.
Martin, I agree that a wire brush will tend to "shine" unbroken paint rather than strip it off; however, I used a
braided wire cup which digs into the surface better than a brush (this is probably more aggressive than most folks need). The advantage was I could take off paint, surface rust, bondo, bird crap, and anything else with just a couple passes. My truck was (is?) crumpled like an old beer can, so I wasn't overly concerned with warping.
