Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Some good progress made already, well done! 

IŽd suggest that you get hold of some polish, like Autosol, Mothers Finest, Maas, or SimiChrome.
Personally i am much in favour of Autosol, but all of the above will polish (and clean) a Jensen boiler to a very high finish.

When it comes to your sightglass, iŽd suggest you save the money for a new one, and simply throw the one you have in a glass of ordinary household vinegar over night.
Tomorrow you can wipe that glass clean again, and if not a light polish will remove any remaining deposits.