Cleaning apparatus and method

An apparatus for use in the treatment of substrates using a solid particulate material, said apparatus comprising:

• (a) housing means having mounted therein a rotatably mounted cylindrical cage;
• (b) access means;
• and
• (c) a multiplicity of delivery means,
• wherein said rotatably mounted cylindrical cage additionally comprises at least one storage compartment for storage of said solid particulate material, wherein said at least one storage compartment comprises a storage volume, a flow path, a first exit port from the storage volume into said flow path, and a second exit port from the flow path into the interior of the rotatably mounted cylindrical cage, wherein said flow path between the first and second exit ports defines a non-linear trajectory, wherein said flow path allows transport of fluids and solid particulate material between said storage volume and the inside of said rotatably mounted cylindrical cage, and
• wherein ingress or egress of fluids and solid particulate material into and out of said at least one storage compartment via said flow path is controlled by the direction of rotation of said rotatably mounted cylindrical cage, and the ingress or egress is dependent on said direction of rotation.