how to clean whiteboard snapshots in general:
+
http://matthew.mceachen.us/blog/how-to-clean-up-photos-of-whiteboards-with-gimp-403.html
+ apparently the URL above is defunct.
+
+ new URL on this topic: https://gist.github.com/adsr303/74b044534914cc9b3345920e8b8234f4
+ requires a bit of gimp knowledge.
+
+====
+
+[untested]
script for whiteboard cleaning in batch can be found in this folder also.
the batch-whiteboard-clean.scm script should go in: ~/.gimp-2.6/scripts