NOVELTY - Preparing a mixture of an oil and a non-oil liquid comprises: cycling the oil and the non-oil liquid together within a loop comprising a cavitation device to produce cavitation bubbles within the oil and the non-oil liquid, where collapse of the cavitation bubbles produces shock waves that produce localized heat and pressure to mix the oil and non-oil liquid; and terminating the cycle once a desired reaction has occurred.    USE - The method is useful for preparing mixture of oil and non-oil liquid, which is useful for preparing biofuel (claimed).    ADVANTAGE - The method: facilitates the transesterification reaction; and reduces biodiesel processing time from the conventional 1-5 hours to less than 5 minutes. The cavitation device, used in the method, enables the use of a reduced amount of catalyst by 30-40% due to the increased chemical activity in the presence of cavitation.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a method for preparing a biofuel comprising providing the loop comprising the cavitation device and a pump, introducing the mixture of an oil, an alcohol and a catalyst into the loop, cycling the mixture through the cavitation device to produce cavitation bubbles within the mixture, where collapse of the cavitation bubbles produces shock waves that produce localized heat and pressure to induce a reaction to convert the mixture into the biofuel and a glycerol by-product, and separating the biofuel from the glycerol by-product; and    (2) a device, for preparing the mixture of an oil and non-oil liquid, comprising a processing loop, means of introducing the oil and non-oil liquid into the processing loop, the pump for pumping a combination of oil and non-oil liquid through the processing loop until a predetermined condition is achieved, the cavitation device disposed within the loop, where the cavitation device comprises many nozzles disposed within a chamber (1810), the nozzles produce cavitation bubbles within the oil and non-oil liquid, and collapse of the cavitation bubbles produces shock waves that produce localized heat and pressure to induce reaction between the oil and non-oil liquid, and an outlet port for removing a reacted mixture once the predetermined condition has been achieved.    DESCRIPTION OF DRAWING(S) - The figure shows a diagrammatic top view of a device with two sets of nozzles.    Volutes (1802)    Steel pipe housing (1806)    Openings (1808)    Chamber. (1810)