Headliner stain question?
 

My '01 PT Cruiser w/sunroof with plugged drains backed up during a
rain storm a couple of years ago and the sunshade in my roof was
closed. That caused a water stain on the front 1" edge of the
sunshade. Can anyone recommend a method to eradicate that stain? I'm
not familiar with working on the felt type material these headliners
are made. Thanks for any suggestions.