Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

hallo!
first of all, let me say i'm not an english speaker so forgive me if
i have mistakes.
i'm soldering a lot, using a cheap 5$ iron. i'm some problems:
after a short while soldering, the the metal part on the iron get
covered with a black crust and after anoter while the metal starts
to literary disappear- and finaly the whole "head" of the iron is
like eaten slowly. what sould i do? sould i use a wet sponge? should
i use a soldering paste? and if i should, how do i use it? i even
tried grinding the black crust with my grinder.is that ok? should i
buy a soldering station? hope you understand what i wrote, and i'm
sure there is a name to the black crust on the iron, and to
the "disappearence" of my iron.
thanks a lot,
mumin.