No-clean fluxes and solder pastes are another sub-set of PCB cleaning that requires special consideration. Most no-clean fluxes are more difficult to clean than rosin-based fluxes and pastes. These contaminates require a cleaner formulated with aggressive solvency, and possibly using inorganic fluids to fully remove any white residue.
Vapor degreasers with spray under immersion or ultrasonics may also be necessary in order to reach the desired cleanliness specification. MicroCare offers several proven formulations that are strong candidates for replacing nPB in these applications.