According to the United Nations Office for South-South Cooperation (UNOSSC) report in 2017, Egypt produced 500,000 tonnes of WCO from various resources including food industries, restaurants and hotels. Based on our previous funded project, we have reported unique properties for Egyptian WCO as it has very high range acidity (≈18 mg KOH/ g oil) due to the extensive usage of oil in the cooking process. Further, the repeated heating of cooking oil for long time produces carcinogenic compounds that have significant impact on people health. On the other hand, high acidity WCO could be valorised into soap, biodiesel and value added chemicals. However, most of these industries requires costly pre-treatment for the WCO to reduce the acidity prior processing. Accordingly, the WCO should be produced within a guideline of specified properties that could detect if it has been extensively used. Low-acidity WCO will prevent several health consequences for Egyptian people and allow industries to easily valorise it into value added chemicals and fuels. The waste cooking oil was subjected to filtration before being fed to the reactor the produced biodiesel was treated to remove any methanol and the characteristics of the final product was compared with the international standards. This work develops a guideline for WCO quality testing to ensure that it has not been extensively used in cooking process. The work also applies supercritical conditions to convert WCO into biodiesel. The response surface methodology was used to conclude the optimum conditions to produce biodiesel.