Pickling or etching titanium is useful to remove scale and contamination (for example particles of other metals or organics). Contamination is important to remove as it may be a site for corrosion, particularly in the case of other metals which may cause galvanic corrosion.
After pickling it may be advantageous to anodise the titanium. The anodising forms a thin oxide layer, but also provides a way of visibly verifying the status of the part (whereas pickling is barely discernable on an otherwise clean looking part). Anodising may also remove contamination.
We can also pickle stainless steel and other materials on request.