Abstract: An exhaust apparatus for a treatment unit of electrical components, preferably wafers, particularly for a spray tool to clean electrical components, is described. To ensure that particles of a size greater than or equal to 0.16 &mgr;m in diameter can be reliably removed from the treatment unit, which particles would otherwise cause contamination of the electrical components, the exhaust apparatus is provided with a main exhaust pipe and a side pipe. The main exhaust pipe has an outside pipe and an inside pipe, whereby the inside pipe is equipped with a number of nozzles. The side pipe connects the treatment unit with the main exhaust pipe and which has an outside pipe and an inside pipe, whereby the inside pipe is equipped with a number of nozzles. The inside pipes are connected with a source of a cleaning fluid such that the cleaning fluid at least intermittently flows through the inside pipes for the purpose of rinsing.