In article ,
"Rusty" writes:
Tried furnox and it works, but smells a bit which lingers for a week on
plastic kettles (from experience). Plus it will strip any nickel plating
off the kettle element if it's left in there for hours, leaving a nice brass
finish.

The smell is deliberate, and an indication you haven't washed it
all out. The dye is an indicator to show when the chemical is
exhausted. I have found it to stain some plastic brush bristles,
and I guess it could stain some other plastic parts.

--
Andrew Gabriel