Removal of a soluble part of a core allows provision of relatively complex three-dimensional geometric shapes in a component. Unfortunately previous leaching arrangements have been relatively erratic such that it is difficult to provide consistency of component form over a batch of components formed. By providing a tank combination which comprises typically a number of dip tanks, it is possible to provide consistency in terms of leach solution efficiency upon cores. Generally leaching solution held within the tanks is adjusted through either a prior calibrating adjustment tank or through agitation or other means in the tank such that the effects of saturation ageing of the leaching solution can be homogenised across all cores subject to the leaching process.