For a large quantity of
script output, I'd hack a perl script together iteratively. Otherwise hand edit with a good editor.
There is unlikely to be an existing automated method of removing control characters from
script output in a way that reproduces what was displayed on the screen at certain important moments (such as when the host was waiting for that first character of some user input).
For example the screen might be blank except for
Andrew $, if you then typed
rm /* and pressed backspace twelve times (far more than needed), what gets shown on the screen at the end of that depends on what shell was running, what your current
stty settings are (which you might change partway through a session) and probably some other factors too.
The above applies to any automated method of continuously capturing input and output. The main alternative is taking "screen shots" or cutting and pasting the screen at appropriate times during the session (which is what I do for user guides, notes for a day-log, etc).