http://www.napoleongrills.com/acces...cd/en-ca/stainless-steel-cleaner-236ml-8fl-oz
This cleaner from Napoleon Grills removes heat discolouration and is supposed to use the same type of acid (phosphoric) as Optiglanz. At only $6.99 it is a bargain and should be available everywhere that sells Napoleon Grills. Might be worth a try?
Myself, I wasn't terribly impressed with the performance of Optiglanz. I still had to use Autosol to remove the worst freckling on my headers (took about an hour). Within a few days the pipes started to turn gold again and a few of the freckles reappeared.