From the company that makes CLR.
We do not recommend that CLR products be used on any metals except for chrome or stainless steel. Any 'polished' finish usually has a coating and most nickel materials are combination metals (containing zinc) and CLR products could compromise the finish.
I have been reading where Sodium Bicarbonate could be a neutralizer for CLR.
CLR® Pro Industrial Products Frequently Asked Questions by The Cary Company. Contact CLR direct at (800) 323-5497.
www.thecarycompany.com