Every electronics manufacturer, whether an original equipment manufacturer (OEM) or electronics manufacturing services (EMS) company, must determine if the unpopulated printed boards entering the assembly process have an adequate level of cleanliness. The question of "how clean is clean enough?" is one that has no definitive answer, as there is no "golden number" for board cleanliness. The issue is a very complex topic, with many critical considerations, and so a single methodology to determine acceptability does not exist. Recognizing this, IPC-5702 has been written to give the printed board or printed board assembly professional some guidance on how to correlate cleanliness related data to electrical function and determine "acceptable" cleanliness levels.