Many thanks, for your comments Asrah ... I'll check out Ganson.
I tried out my first egg skin today (5 more pending in a day or so). I have applied glycerine per Colucci's instructions.
The skin does not seen to want to inflate very easily ... perhaps I need to enlarge the hole, as I used a piece of coathanger. Also, the hole I made is not perfectly round, as Colucci recommends, but is a little ragged.
I'll give the skin some time to absorb the glycerine. It will also take some time on my part to become familiar with its properies.
Your guess is correct, though ... these things seem to be pretty tough and durable.