Hoshiazaki AM-50BAE-AD Ice Machine Evaporator Corrosion

[Howard Duncel]

My 12 year old Hoshizaki AM-50BAE compact commercial ice maker is working well, but over time the nickel-plated evaporator has become partially covered by spots of greenish-black Nickel Oxide corrosion.  Because the cubes form directly on the evaporator, I'm concerned about potential ingestion of small amounts of the material.

While I know the evap could simply be replaced to resolve the issue, the part alone is $400+ and, given it's age, it's financially questionable.  I've tried various things to remove the corrosion with limited success - for example, soaking & scrubbing with vinegar/water and/or aqueous ammonia solutions.  How else can I remove the corrosion without damaging the Evaporator, and preferably without removing it?  I have considered electrolysis to remove the corrosion and then re-nickel plate it, that's also a lot of trouble without removing the evap.

Any thoughts or suggestions are appreciated.  Thanks in advance!

Howard