Como Hacer Biodiesel > Magnasol and other Finishing agents:

After the glycerin separation process, biodiesel still contains contaminants such as soaps, unreacted or partially reacted triglycerides, water and methanol. These contaminants are traditionally removed by water-washing the biodiesel. Another option is to use a substance called Magnesol, produced by the Dallas Group. Magnesol allows you to eliminate the water-wash step and also the subsequent liquid separation and drying of biodiesel. In addition, Magnesol has a high affinity for methanol and water and can remove these contaminants from the finished product. Typically a mixture of 1-2% by weight magnasol is added to the biodiesel, usually following methanol distillation and glycerin decanting. The mixture is then agitated for 20 – 30 minutes, and then filtered through a <1 micron industrial filter.

References on Magnesol:

Biodiesel Magazine Article on Magnesol