Sodium metasilicate - is it a cleaning agent?

Sodium metasilicate is not a cleaning agent by itself. It is a VERY strong base. The pH of a 1% aqueous solution is about 13. In moist air it is corrosive to metals like zinc, aluminum, tin and lead, forming hydrogen gas. As a strong base, it reacts violently with acids. A major use is as a builder (a material that enhances or maintains the cleaning efficiency of a surfactant, Principally by inactivating water hardness) in soaps and detergents.

It may be used as part of a component in a chemical degreaser, where it would react with fatty acids (animal grease) to form a soap, Which is then rinsed away. Sodium silicate, On the other hand, is an abrasive white powder frequently used in things like toothpaste. It does not clean by itself either. Not something I would recommend for household use.