In a first aspect, this invention relates to an apparatus for applying a liquid onto surfaces within internal cavities in an object (1). The apparatus comprises at least one vessel (8), an upwardly open through (10) formed with at least one bottom hole, which trough is located above the vessel (8) and on which the object (1) is placeable, as well as two conduits (24, 25) communicating with the vessel as well as the trough, viz. A feeder (24) from which liquid via the trough (10) from below may be brought to ascend up in the internal cavities within the object (1), and an evacuation conduit (25) provided with a cut-off valve (30) through which excess liquid after finished processing of the object may run back down into the vessel (8). Further more, the invention also relates to a method for applying a liquid onto surfaces within internal cavities in an object (1).