The three main ingredients in sugar soap are sodium carbonate, sodium phosphate and sodium silicate. There is actually no sugar in the list of ingredients for the soap.
Sodium carbonate is the first ingredient in a compound called "trisodium phosphate," or more commonly TSP. It easily dissolves in water, making it a good choice for a cleaning solution. Sodium phosphate is the second ingredient in the TSP formula and acts as a cleaning ingredient when mixed with sodium carbonate and sodium silicate. Sodium silicate is the abrasive compound in sugar soap. This mild abrasive scrubs away some stains and hard-to-remove dirt.
The soap receives its name from the fact that when all the necessary ingredients are combined, the result resembles common table sugar. It is a generic name used to describe a popular chemical cleanser and paint priming solution, available in powder and liquid forms
The soap is used as a commercial cleanser to prepare walls for painting or wallpapering, and is very useful in cleaning nicotine stains, grease, pet odors, germs and bacteria; in addition to sanitizing interior walls and floorboards. Because of its abrasive nature, the soap should not be used on painted or glossed surfaces as it removes the paint or gloss.