They're either absorbed through your skin or inhaled. I think most parents would not consider keeping their children away from an area that's being cleaned. But if you're spraying a chemical cleaner with a child wrapped around your knees they're very likely to inhale it. I think being conscious of the exposure and trying to keep the kids exposure to a minimum is the best way to protect your family. Another problem with children and dangerous household products is storage.
Kids are like magnets to the wrong place at the wrong time.
Salt is very corrosive but used in moderation can be an effective cleaner. One of the most powerful natural cleaning solutions we've ever made was a simple paste of salt and fresh lemon juice. It does an amazing job of cleaning copper bottom pots or anything brass. Since copper and brass are non-ferrous metals, you don't need to worry about corrosion. Likewise natural oven cleaners which use mixtures of baking soda and water work well as the oven is usually porcelain lined.