The size of your document can be very important. If you delete same old transactions, the size will increase.
This is normal because skrooge keeps the history of all modifications for the undo/redo mechanism.
So, if you want to reducte the size of your document, you just have to clear the history.
How to avoid Skrooge freeze ?
Sometimes, Skrooge freezes.
Most of the time is due to settings.
So, you just have to try:
rm ~/.kde/share/config/skroogerc
If, this doesn't work, then try:
rm ~/.kde/share/apps/skrooge/skrooge_print.rc
rm ~/.kde/share/apps/skrooge/skrooge_file.rc
rm ~/.kde/share/apps/skrooge/skrooge_importexport.rc
rm ~/.kde/share/apps/skrooge/skrooge_undoredo.rc
rm ~/.kde/share/apps/skrooge/skrooge_operation.rc
rm ~/.kde/share/apps/skrooge/skrooge_scheduled.rc
rm ~/.kde/share/config/skrooge-appletsrc
rm ~/.kde/share/config/skrooge_filerc
rm ~/.kde/share/config/skrooge_operationrc
rm ~/.kde/share/config/skrooge_importexportrc
rm ~/.kde/share/config/skrooge_searchrc
rm ~/.kde/share/config/skrooge_scheduledrc
rm ~/.kde/share/config/skrooge_unitrc
rm ~/.kde/share/config/skrooge_undoredorc
