Care for a Rusted Iwachu Tetsubin

[bohoinparadise]

Dear teachatters,

A while ago I was given an old Iwachu Tetsubin that appears to have rusted on the inside and has stains (I suspect from being used on top of a stove) on the outside. As I began to research ways to clean it I realized there is much conflicting information on the web, with some suggesting scrubbing it with a brush and others insisting that the rust is actually a flavour enhancer and thus should be appreciated.
Could anyone please recommend a proper cleaning technique for this iron cast teapot?

[Teaism]

You can check this site for general understanding:

http://hojotea.com/categ_e/tetsubin.htm

[bohoinparadise]

Thank you, I will try their suggestion to boil tea leaves for rust reduction.