Besides the pH, the biggest difference is how neutrals and alkalines clean. Neutral cleaners clean via a mechanism of emulsification, that is, they surround the oil molecules with a soap cage called a micelle. This micelle is formed by agitation and impingement of the oily surface.

The micelle prevents the oil from re-attaching to the metal's surface. Once the agitation is stopped, the micelle will release the oil unchanged to the water's surface where it can be recovered. Once the excess oil is recovered, the neutral soap is available for cleaning again.

Alkalines, on the other hand, chemically react with most oils via a process called saponification. Saponification chemically changes the oil to a partially soluble soap which cannot be easily separated from the water. Alkalines get consumed during this process of saponification and the process cannot be reversed. Another big difference is how the metal surface will look once cleaned. Neutral cleaners are all organic, and are very free-rinsing. Therefore, once the surface is cleaned of oil, the soap will rinse off completely leaving negligible residue behind. Because a metal surface has an overall positive charge and water is polar (one side positive and one side negative), a truly clean metal surface will bead water. Visually speaking, the beaded water looks the same on an oily surface and a clean surface. Surface cleanliness must be determined using other methods. Because alkaline cleaners do not rinse easily (as anyone who has had them on their hands knows), there is soap residue left behind after cleaning that will not rinse off easily. Because the soap residue will break the water's surface tension, the water will lay down flat and sheet on the metals surface (often referred to as waterbreak free). Parts cleaned with alkaline soap are not truly clean because of the soap residue left behind.

Find out more about neutrals at: www.neutralcleaning.com