We need to remove RMA solder flux on indium/lead soldered subassemblies. Most aqueous cleaners attack this solder.
According to the Materials Handbook by GS Brady et al, indium lead solders are alkali resistant solders. Rosin based RMA fluxes are best cleaned by alkaline/saponifying cleaners with no conductive cations such as Detergent 8.
The organic amine in Detergent 8 forms a water soluble soap with the rosin. Because Detergent 8 is cation free, it cannot leave conductive residues. We recommend using a 3% Detergent 8 solution for ultrasonic immersion cleaning or a 5% Detergent 8 solution for manual cleaning of indium/lead soldered subassemblies.
Detergent 8 is a hazmat that most package sizes must ship by ground. You can ship a 5 gallon jerrycan of Detergent 8 by air.