[TR] Cleaning Cardboard Radiator Duct

[P Caffrey]

List,
I just purchased and received a TR4A shroud/duct for the radiator, used
of course.  The duct is in fairly good shape for something that's been around
for over 40 years.  There is noticeable rust on the rivets, and it's dirty
with black soot-like material that comes off on the hands while handling.  How
do I clean this duct to prepare it for painting?  I googled "cleaning
cardboard" and found a link for cleaning cardboard game board boxes.  The
suggestion was to immerse the box in a tub of lukewarm water and then let dry,
thoroughly.  I don't think I want to do this with the duct.
Thanks for any
suggestions,
Pat
TR4A '67