I do not know where to buy Brownell's in Canada... I believe shipping
accross the border is not allowed here. Is there a Canadian source?

Caswell Plating looks interesting. I also found that KBC Tools sells a
version. Anyone know which works better? What about odour, toxicity,
& safe storage are all issues for me.

Also, how does one know when the solution is depleted? Or it just
doesn't blacken.

Distracted