"A wise old man told me that the water in a quench bucket (which is the bucket a blacksmith uses to cool iron rapidly by dunking the hot iron in it) was the best cure-all for poison ivy that he had ever used. When a friend came down with a bad case of poison ivy and told me that calamine lotion wasn't working, I shared the wise man's story. She promptly filled a plastic spray bottle with my dirty quench water and coated her arms and legs. A day later she returned to the shop wanting to sell the "magic elixir" to the public. The theory? Heavy concentrations of iron in the water accelerated the drying up of poison ivy blisters." 
Muscle soreness after exercising can be a big disincentive to continue on a healthy fitness program. That’s why the subsequent findings of that UNC group are so important. The scientists gave vitamin C supplements (3,000 mg/day) or placebo to a group of 18 healthy men for two weeks before and four days after performing 70 repetitions of an elbow extension exercise. 23 Not surprisingly, considerable muscle soreness ensued, but it was significantly reduced in the supplemented group. The release of creatine kinase, an indicator of muscle damage, was also attenuated with vitamin C, compared with the placebo group. Blood levels of natural antioxidants fell significantly in placebo subjects, while vitamin C supplementation completely prevented this change. Results such as these suggest that the supplemented group would be much more enthusiastic about exercising the next day!
The known health risks of secondhand exposure to cigarette smoke—to the heart or lungs, for instance—raise questions about whether secondhand exposure to marijuana smoke poses similar health risks. At this point, very little research on this question has been conducted. A 2016 study in rats found that secondhand exposure to marijuana smoke affected a measure of blood vessel function as much as secondhand tobacco smoke, and the effects lasted longer. 88 One minute of exposure to secondhand marijuana smoke impaired flow-mediated dilation (the extent to which arteries enlarge in response to increased blood flow) of the femoral artery that lasted for at least 90 minutes; impairment from 1 minute of secondhand tobacco exposure was recovered within 30 minutes. The effects of marijuana smoke were independent of THC concentration; ., when THC was removed, the impairment was still present. This research has not yet been conducted with human subjects, but the toxins and tar levels known to be present in marijuana smoke (see “ What are marijuana’s effects on lung health? ”) raise concerns about exposure among vulnerable populations, such as children and people with asthma.