I found somewhere on the net about how they used to use Soya Sauce on chemical burns in the war. After burning myself on the stove (not a serious burn but enough for it to of blistered) I poured soya sauce on to it. Almost immediately the pain subsided and I never got a blister. One of my students accidently poured boiling water over his hand and he remembered me talking about soya sauce, so he poured it over his hand. He also said it took the pain away and it never turned into anything.
1. Vinegar: for sun burns. Saturate a cloth with white vinegar and apply it often. Relieves the sting, heat, and itch (apply when you feel the symptoms return). Amazingly, the smell goes quickly, so no need to worry about the idea of walking around smelling of french fries!
2. Soy Sauce: for grease burns (also- iron and other household burns). I applied Soy Sauce on a grease burn, 30 minutes after (the pain wasn't letting up), and I never felt it again. I found 'Liquid Aminos' to have better results than regular Soy Sauce, possibly because is just soy sauce and water, and not fermented (tastes great too!)
**of course these remedies probably won't feel very relieving if done on broken/open skin!