did anybody see these on ABC new inventors, 30ltr recyclable plastic kegs here are the links
http://www.ecokeg.com/index_new.html
http://www.abc.net.au/newinventors/txt/s1169711.htm
use a pair of pliers push down on the oring then grab the centre disk & twist it to the right, it should then drop down. then unscrew the large flanged cap leaving spear to pull out.
