Aptly named soap scum is a vile nemesis mankind has been battling since we began bathing indoors. For some, feeling the press of a losing battle, the temptation to return to showering under waterfalls and bathing in river eddies — actually that sounds delightful — grows with each new layer of scum on their shower door. What is soap scum? Why does it intrude upon our tranquil hygiene rituals? What can be done to turn the tide and claim our victory?The soap scum, it’s terrifying this poor ladyIn order to conquer our bathtubs, we must first understand our enemy. Fatty acids are used to adjust many properties of soaps including the lather quality, cleaning aggression, and conditioning effects. Mineral ions (most notably calcium and magnesium) found in all unfiltered water sources, react with these fatty acids. The resulting precipitates get left behind as the water dries, and build up into a scaly surface.Chemical process involvedOne way to mitigate some of this buildup is to reduce the amount of soap residue available for the ions to react with. Dr. Squatch’s Soap Saver accomplishes this feat in the most troublesome area of your shower, just below where you store your bar of soap. By raising the soap off the shelf, the Soap Saver keeps your bar out of the grimy water that pools around it. This allows your soap to air dry faster, minimizing the slow leaching of soap that will soon join the layers of built-up scum on your wall.Dr. Squatch Soap Saver and Nautical Sage soapWhile soap scum is not just an eyesore, it’s also not quite on the CDC’s watchlist…yet. As soap scum builds up it creates an environment which harbors bacteria, molds, mildews, and even algaes. If you think the scaly scum is unsightly then the rainbow of bacterial and moldy colors won’t be an improvement…unless you can get someone to forge Jackson Pollock’s signature in the corner somewhere. Soap scum itself, being simple mineral deposits, is odorless but many of the biota contributing to this new ecosystem will bring with them their own funk. Most bathrooms have enough of that as it is, so it’s time to start fighting.Never mind, no shower door could ever look as bad as this…A couple cleaning suggestions that cropped up more frequently than others, however, included Bar Keepers Friend or creating a 1:1 mixture of hot vinegar and blue Dawn (try 2:1 if it’s too sudsy…some of the Dawn bottles are extra concentrated) sprayed on, allowed to work in for 10-15 minutes or longer, and wiped off.Once you get your shower clean there should be no reason to sound the retreat. With prevention and your personalized method of deep cleaning, soap scum won’t stand a chance. Good luck, may your shower doors be ever crystal clear and your walls squeaky clean.The best strategy should exploit the weaknesses of our adversary. Short of taking out a second mortgage to filter all the water we shower with, we are unable to prevent soap residue from interacting with minerals in the water. This leaves us attempting to prevent the precipitates from sticking to the walls of our showers. Lemon oil and Rain-X are both suggested prevention methods (also some good treatment recommendations at that link). Of course, preventative measure will only work on a clean surface. For that there are endless products on the market and the variety of successes described in reviews suggests that soap scums are not all created equal. There are so many variables when considering all the different types of soaps, sources of water, and surfaces of bathtub material that there may be a bit of trial and error in finding a solution that will win you your war.