Hydrogen peroxide (industrial strength)
is used for cleaning porcelain.
A combination of lemon and vinegar makes an excellent
brass cleaner.
Ammonia hides hairline cracks in glassware by removing
dirt from within the crack and allowing it to close. This
does not, however, return the glass to its original strength.
Dunking SOLID brass for a short time in household bleach
will make it look old.
Tarnished silver? Place aluminum foil on the bottom of
a glass container and fill with warm salt water. Place
the silver item to be cleaned on the aluminum foil and
let it sit until the tarnish is removed. You can also
use your sink, depending on the size and quantity of item(s)
needing to be cleaned.