If you hold the stamps of Austria, up towards the light, at about 15º from the horizontal plane,
you should notice bars of stamp surface that are shiny compared to the duller areas between
the bars. This should work on almost all Austrian stamps that were issued with varnish bars.
Just avoid soaking in too hot of a soaking bath when removing the paper from their backs, so
as not to wash the varnish off. I have never had a problem telling these different stamps apart.
