For the purpose of this subpart:
(a) The ``core'' of the forging subcategory shall include forging, artificial aging, annealing, degreasing, and sawing.
(b) The term ``ancillary operation'' shall mean any operation not previously included in the core, performed on-site, following or preceding the forging operation. The ancillary operations shall include forging air pollution scrubbers, solution heat treatment, and cleaning or etching.