Since indoor plumbing and drainage systems became commonplace in the average home, the problem soon arose. What do we do when it clogs; inevitably it will. Back in the 1970's and probably earlier, the answer was Liquid Plumber or it's equivalent. Another common solution (pun intended) was Sodium Hydroxide, usually under the trade name of Drano or caustic soda lye. Now that lye is nearly impossible to get because of anti-drug laws, the ingredient of choice is sulfuric or muriatic acid. These chemicals work by dissolving the material somewhat so that it will pass through the drain. My mother used lye on a washcloth yours truly let pass down the drain and it ate it up in short order. All of these chemicals are very good at removing organic material that finds its way into the drains. Nevertheless, these chemicals are not unlike those used in both world wars to snuff people out. They can cause eye, skin and internal injuries just by inhaling them; much less other means of ingestion. There is another hazard to using chemicals to clean drains, or even toilets for that matter.
The same acids that corrode organic matter can do a number on metal. They will even damage and eat though stainless steel, removing the coating and shortening its life. They chew through chrome, brass and other metals; weakening them to the point of failure. The real danger is from flooding when a drain pipe is eaten through (because any residual hair in a trap will hold acid or lye. The flooding destroys vanities, flooring, joists, drywall and could even cause electrical problems with a house. Another clear and present danger is in those tablets made of bleach (sodium or calcium hydrochloride a strong base similar to lye) meant to drop into the toilet tank. These corrode metal, plastic and rubber parts to the point of failure. If you think about it, there are only two bolts and a layer of rubber less than 3/8 of an inch think protecting your home from certain destruction. If these bolts or gaskets fail on your toilet, it could potentially spill five gallons per minute on your floor and walls, effectively destroying them. Just the fill valve or flapper corroding could waste that much water and the only way you would know would be on your next water bill. I'm certain that a lot of handle jiggling is the result of using these vile chemicals. Even the blue and and green ones will tear things up.
So what is a homeowner to do about clogged drains and nasty toilets? The former is prevention. Remove hair from all plumbing fixtures and not washing it down the drain, not overusing the garbage disposal, etc. When the inevitable happens, a mechanical drain cleaning snake available at hardware stores and home centers is the best bet. It takes a lot less mechanical inclination to to use these than the resultant repairs on a damaged drain from using chemicals. Even a call to a plumber is cheaper by far. Toilets are even easier. Get a cleaner that snaps on the bowl, or break out the cleaner and a bowl brush. The five minutes a week cleaning this out is still a lot better than a home insurance claim for a $100,000 or more. Believe me, I worked in property management for five years and have seen the results of using chemical warfare improperly. An ounce of prevention is worth a couple tons of cure.