In an apparatus for efficiently and thoroughly cleaning tramp oil and contaminants from machine coolant; a tank 12 having three compartments 32, 52 and 66 with a quietener baffle 58 located between the first compartment 32 and the main compartment 52, a torturous path between the main compartment 52 and the clean coolant storage compartment 66, and an agglomeration baffle 76 between the main and storage compartments 52, 66, respectively, is provided. Further, the flow quietener baffle 76 is arranged within the tank 12 so that material flowing from the first compartment 32 to the main compartment 52 will flow generally down the quietener baffle 58 and arrive in the main compartment 52, substantially at the level of the interface 46 between the floating light material 42 and the heavy material 44 with a minimum of disturbance to interface 46. Rapid and complete floatation of oily material containing heavy contaminants is achieved by the addition of aeration bubbles 62 within the first compartment 32.