We can use:
- mechanical polishing
- chemical polishing
Peneplain is an eroded mountain.
The pressure sandblaster will be quicker, but I'm not sure if the siphon sandblaster will blast the rust off the metal as proficiently as the pressure blaster. It would likely not clean the metal as well.
Glacially eroded valleys are normally U-shaped.
because they are very old and have been eroded by the elements
Argon
Depends what the agents of erosion are. For example: If it was ice, the area would be scoured clean. If it were water or wind, the eroded material may have been carried off, leaving only the eroded surface.
You can clean metal by using some stuff to clear it off and away it goes.
A powerful movement the USA government is the Clean Water Act
Pickling. http://en.wikipedia.org/wiki/Pickling_(metal)
The best way to clean earrings with out tarnishing the metal is by using rubbing alcohol. This will not only clean the earrings, but it also works as a disinfectant. Rubbing alcohol does all this without tarnishing the metal.
The benefits of getting a metal trash can are that it is easier to clean and able to recycle when it is done. A plastic bin is harder to clean and is not recyclable
hydrochloric acid
Depends on what the "green" is. But I'd suggest a metal polishing compound.
it is being eroded by the wind and sea
Peneplain is an eroded mountain.
Yes and it can also dissolve a metal nail after about 1 or 2 weeks.
Metal polish like Autosol