For the purpose of lubricating a cavity, particularly an annular cavity in a tool for forging blanks produced by powder metallurgy, a lubricant spray is directed towards a limited portion of the cavity surface and the nozzle is displaced such that impingement area of the spray against the cavity sweeps over the entire surface of the cavity. The impingement surface of the lubricant spray is adapted to cover the radial extension of the annular cavity, the nozzle being displaced along the periphery of the cavity. An apparatus for carrying out the method includes a carrier (10) with a mounting (11) for a swinging arm (12) carrying a spray nozzle (14). The carrier (10) is adapted for being positioned for mounting of the arm coaxial with the axis of the cavity, the arm (12,13) being arranged for positioning the nozzle (14) over a peripheral portion of the cavity. Means (31) are arranged for causing the nozzle (14) to circulate along the periphery of the cavity.