During the first takeoff for the day some smoke appeared in the aft cabin. The smoke dissipated leaving a strong burning odour. The aircraft returned to Melbourne where a normal landing was carried out. Investigation disclosed that the right engine had been internally washed during the overnight service. Ardrox 6345, an aqueous based cleaning fluid, had been utilised. This was the first time that this product had been used in this application. It was found that the approved rinsing procedure had not taken into account the foaming effect of the Ardrox 6345 and some residual fluid had remained in the hot bleed air section of the engine. This had been evaporated and burned during the takeoff. The operator has revised the rinsing procedure to preclude a repetition of this event.