we use a don carlos knife but a strong thin scraper will do
if its externally beaded then take out the rubber gasket from the inside first. place a scraper inbetween the rubber and the frame and lever the rubber out. once the rubber is out go outside and push the glass inwards, then take the beads out.
if its internally beaded then you just have to lever the beads out
                
 levi lewy
                
 July 2010