Cleaning antique carafes

I have inherited several small antique carafes, which I would like to use (for extracts used to flavor Scandinavian aquavit).

Carafes are blown (not pressed) and probably 75-100 years old.  Several have whitish deposit in the bottom, presumably from water evaporating.  The necks are so small, that I cannot get a brush inside (and design does not allow 'tools' to reach through to the bottom anyway).

What is the recommended method to remove the deposits?

rice and white vinegar - swirl it around. It may be residue or glass may be 'sick': http://www.cutglass.org/articles/sick.htm

It was residue, and your method worked like a charm.

Thanks,