2. Notice the change in color. The reaction is taking place.

4. The chemical reaction has happened.

5. The waste oil on the left turns very dark
The waste oil on the left turns very dark. The higher the fatty acid content, (i.e. the more the oil has been used), the darker the oil will be.

6. The glycerine is starting to settle out.

7. The glycerine has clearly separated out.

8. Prewash with 5% water before draining off glycerine
Prewash with 5% water before draining off glycerine. This helps stop the reaction and helps remove some of the smaller particles of soap that is still suspended.

9. After adding the water and shaking let the mixture settle
After adding the water and shaking let the mixture settle. By standing it upside down, it will be easier to drain the glycerine layer off.

10. The glycerine layer has settled fairly well.

11. The glycerine layer on the virgin oil is much lighter than the waste oil.

12. Four hours later, and after a quick trip to Lowe’s, we can now drain the glycerine layer off.