Removal of the chlorides is essential. In practice this first involves physical cleaning (with a wooden or even metal pick) to remove the bulk of the chlorides and then chemical treatment. One chemical treatment is soaking the object in a 5% sodium sesquicarbonate solution. This serves to neutralize the acid that attacks the metal as well as converting the reactive cuprous chloride to largely inert cuprous oxide. The oxide may coat the artefact with unsightly but harmless black spots or generally darken the metal.
The duration of soaking may be days to weeks or even a year for severely contaminated objects. The sesquicarbonate may remove copper from the artefact as it forms a complex ion with copper. Amateurs report that the patina may be stripped from the artefact but this is when the solution is boiled so that the carbonate rinse removes the chlorides in hours rather than the cool bath of long duration used by professional conservators.
Soaking in sodium carbonate—which does not form a complex ion with copper and is unlikely to affect the patina but is slower than the sesquicarbonate—or benzotriazole aqueous solutions may also be used. The carbonate is similar in effect to the sesquicarbonate. The benzotriazole does not remove the chlorides or neutralize the acid present but acts as a physical barrier to water, oxygen, and chlorides and so can be used as a final step in all cases but as a first or only step in only minor cases.
Use of tap water for initial carbonate rinses is fine as any chloride content in the water is low compared to the content found when the chlorides from the contaminated artefact have dissolved into the water. Later rinses should be with distilled water though the chlorine of a chlorinated town water supply is likely to have evaporated from tap water inside 24 hours and therefore will not further contaminate the object.
Instead of rinses, electrolysis may be used, often with sodium carbonate as the electrolyte and mild or stainless steel as the anode. This converts the cuprous ions to elemental copper. Elemental copper released from the chlorides may be redeposited on the artefact as a pinkish coating. A coin may take only hours, whereas a large artefact, such as a cannon, may take months.
Once treated, the specimen should be held in a dry environment and periodically inspected for recurrence of bronze disease as no long-term treatment has been confirmed.