Detergents are better cleansing agents than soaps because they can be used even with hard water. The charged ends of detergents do not form insoluble precipitates with calcium and magnesium ions in hard water. Detergents have a stronger cleansing action than soaps and are more soluble in water than soaps.

A detergent is a surfactant, usually alkylbenzenesulfonates , a family of compounds that are similar to soap but are more soluble in hard water, because the polar sulfonate (of detergents) is less likely than the polar carboxyl (of soap) to bind to calcium and other ions found in hard water.

Soap is less effective in hard water because it reacts to form the calcium or magnesium salt of the organic acid of the soap. These salts are insoluble and form grayish soap scum, but no cleansing lather.

Hence, detergents are better emulsifier than the soaps because in hard water detergents do not form scum whereas soaps do.

When grease or oil (non-polar hydrocarbons) are mixed with a soap- water solution, the soap molecules work as a bridge between polar water molecules and non-polar oil molecules. Since soap molecules have both properties of non-polar and polar molecules the soap can act as an emulsifier.

Soap is an excellent cleanser because of its ability to act as an emulsifying agent. An emulsifier is capable of dispersing one liquid into another immiscible liquid. When soap and soiling oils are mixed, the nonpolar hydrocarbon portion of the micelles break up the nonpolar oil molecules.

Lecithin is found in egg yolks and acts as the emulsifier in sauces and mayonnaise. Lecithin also can be found in soy and can be used in products like chocolate and baked goods. Other common emulsifiers include sodium stearoyl lactylate, mono- and di-glycerols, ammonium phosphatide, locust bean gum, and xanthan gum.

Soaps and detergents are made from long molecules that contain a head and tail. These molecules are called surfactants; the diagram below represents a surfactant molecule. The head of the molecule is attracted to water (hydrophilic) and the tail is attracted to grease and dirt (hydrophobic).

Surfactants are used a lot in body washes and shampoos to make them foamy, and to cleanse dirt and oil from your skin and hair. At Dove we use alternative cleansing ingredients (some of which come from naturally occurring amino acids) that still provide a foam but are proven to be milder to the skin than surfactants.

Dish soap is used as a surfactant, both when washing dishes and applying herbicide to plants. While it might effectively remove grease and food from plates, dish soap probably should not be the “go-to” surfactant for herbicides.

Sodium stearate is a good example of a surfactant. It is the most common surfactant in soap. Another common surfactant is 4-(5-dodecyl)benzenesulfonate. Other examples include docusate (dioctyl sodium sulfosuccinate), alkyl ether phosphates, benzalkaonium chloride (BAC), and perfluorooctanesulfonate (PFOS).

A non-ionic surfactant has no charge groups in its head. The head of an ionic surfactant carries a net charge. If the charge is negative, the surfactant is more specifically called anionic; if the charge is positive, it is called cationic.

Surfactants have an HLB value – the higher the number the more hydrophilic (water soluble), the lower the number the more lipophilic (oil soluble). Oils and applications have an HLB requirement. Matching the HLB value with the HLB requirement will give good performance.

Carboxylates are the most common surfactants and comprise the carboxylate salts (soaps), such as sodium stearate. More specialized species include sodium lauroyl sarcosinate and carboxylate-based fluorosurfactants such as perfluorononanoate, perfluorooctanoate (PFOA or PFO).

Soap, shampoo, hair conditioner and toothpaste all contain surfactants which gently cleanse the scalp, skin, hair and teeth. These compounds create a pleasantly foamy reaction when mixed with water.

Nonionic surfactants are neutral, they do not have any charge on their hydrophilic end. Nonionic surfactants are very good at emulsifying oils and are better than anionic surfactants at removing organic soils.

As with any cleaning agent, vinegar has its limitations: it’s neither a surfactant nor, at roughly five percent acetic acid by weight, a broad-spectrum disinfectant.

Bicarb or baking soda (sodium bicarbonate) is a pH adjuster. It isn’t a water softener and it doesn’t have any surfactant qualities.

The combination of dish soap and vinegar is highly effective for a few different reasons. However, vinegar alone will simply run off of most surfaces, while dish soap is too thick to use as a spray. But when you mix them together, you get an effective, sprayable cleaner that sticks to any surface!

Wash mold off hard surfaces with soap and water, or use a mix of vinegar and hydrogen peroxide to kill mold. When cleaning mold, always wear a filtered facemask, so you won’t inhale spores. Use hydrogen peroxide instead of bleach in the laundry.

In a spray bottle, combine 1/3 cup ammonia, 1/4 cup white vinegar, 1/2 cup baking soda, and 7 cups of water. Spray down the shower, then watch as the vinegar and baking soda together create a cleansing, bubbling foam.

Let the shower head soak for several hours. For an especially dirty fixture, leave it overnight. However, if you have a brass, gold, or nickel-coated shower head, remove it from the vinegar after 30 minutes. Any longer than this could damage the finish.

Regularly spraying vinegar on bathroom surfaces and letting it air dry kills mold spores and prevents growth. Make sure there’s proper ventilation in the bathroom and install an exhaust fan if you don’t have one. If you can, wipe down the shower with a cloth or squeegee after showering.

Here, the best shower cleaners out there now.

• Best Overall: Earth Friendly Products ECOS Shower Cleaner.
• Best for Hard Water: The Bucko Soap Scum and Grime Remover.
• Best for Soft Water: Method Foaming Bathroom Cleaner Eucalyptus Mint.
• Best for Mold: Mold Armor Mildew Stain Remover Plus Blocker.