How to get rid of Microsoft dumb quotes, e.g. \222 for apostrophe?

[Endless Story]

My apologies as I know this topic has been covered before, but despite
much Googling I haven't found a simple, direct solution to the
problem.

I have just started seeing lots of nasty stuff like \222 instead of
apostrophes in working on text files in Emacs on XP, then trying to
reformat these files for LaTeX. My guess is I picked this garbage up
when I copy-and-pasted some material out of Word, though I'm not
certain. Emacs on XP displays these characters fine when I am just
working with a .txt or .org file - which is why I didn't pick up on
the problem earlier.

I am looking for a simple function or .el package that will remove the
garbage and replace it with latin1 encoding or whatever is acceptable
to LaTeX. I have done lots of Googling but haven't come up with
anything that doesn't refer to gnus (which I don't use) or which
doesn't get me lost in talk of this encoding system or that. A search-
and-replace function will do fine - and I will even write it myself if
someone gives me a tip on how to get started (again, I'm not a lisp
expert).