Piercing in the scrap area of material and "leading-in" to the actual geometry to cut is standard operating procedure in most waterjet applications. This avoids placing a large blow-out blemish from the initial piercing on the surface of the part. At the end of a cut, a lead-out may be required to remove any "nib" from the lead-in area.

Various types of lead-ins and lead-outs can be experimented with for different materials and thicknesses. Figure 9 shows a few examples of lead-ins and leads-outs.