Second in a series of seven videos, DVD-82 explains three techniques: mechanical scrubbing, pumice scrubbing, and chemical cleaning. Visual examples of acceptable and rejectable conditions are provided, illustrating the range of allowable variation. Operators are shown how improper handling will affect the product immediately and down the line. Pre-image cleaning may be the most critical processing step in the fabrication of multilayer boards, and perhaps the most neglected. It is important to understand the theory of the cleaning operation, and why it is essential to do it right. Time: 21 minutes.