Hi,
I have been lucky to come into several shards of Ancient Roman glass
with beautiful patinas. I would like to clean these pieces before
setting them. In addition to caked dirt (?) that can be gently
scraped off, I would also like to make them as shiny as possible. I
have seen finished jewelry embedded with very shiny pieces.
Would anybody be able to assist me with personal
experience in this matter? I would not want to do anything to damage
those patinas… 
Thanx and keep shining,
Devora
Hi Devora
Ancient glass will decay quite quickly especially once the surface
has been cleaned. The patina will almost certainly also be lost.
Museum conservation usually consists of stabilisation and if it is
going to be put on display it is treated with a resin - the type will
depend on the type of glass. Glass is silica, potash or soda based
but will contain other materials as well these determine how it will
decay and what treatment is needed to stabilise it. Initially the
best course of action would be to take it to your local museum
conservation department (before too much of the surface has been
cleaned away) they will be able to determine the type and then
suggest the surface and resin treatment to apply this will give it
its shine. As well as being a jeweller I am a certified archaeologist
and have dug up lots of glass including roman. The normal procedure
is to leave soil on or store it wet until it can be stabilised in a
lab. I have used beach glass for jewellery but this is recent in
comparison to yours - I normally rub this with either olive or a
silicone based oil to displace the salt and gunge from the surface
pores that have developed. I work the edges with a fine stone SLOWLY
on my flex-shaft to remove any sharp bits and give a better shape for
setting.
Hope that this helps
Robin Key, FSA Scot.
Clavis Jewellery
Aberdeen, Scotland