Kris

Maybe its an Antipodean thing, or we dont have oyster knives to worry
about.  I remember my dad using this method with long-neck beer bottles
when he needed a small container for a particular purpose and an old tin
can wouldn't do. He also wasted money on a device that achieved the same
purpose, being a steel wheel on an adjustable arm, which could scribe
inside and outside a bottle perimeter, and then a combination of heat
and ice would snap the glass along the scribe line.  Good in theory,
broken glass nearly took his thumb off and it was consigned to the bin
within a week.

Denis