Soft metals, such as copper, brass, bronze, and aluminum, require certain care be taken when applying any chemical to the surface; or, allowing any chemical to dirp or rinse onto the surface..
The best way to prevent any adverse reactions is to keep the chemicals from coming in contact with soft metals. While this may not always be possible, it is encouraged to take whatever precautions are available. Some suggestions include covering the areas or dying the chemical/water flow to direct it away from coming in contact.
In many instances, the only reaction will be in the surface coloration of the soft metal and the integrity of the metal will remain in tact. However, we are chemical manufacturers and not metallurgists, so we can only attest to the appearance of the soft metal after chemical contact.
Proper testing is always recommended on all surfaces with any product to determine suitability.