refinishing glass vase

Usually this means that the water has leached out some of the alkali, so that you have a silica-rich layer. Alternatively it could be a deposit of calcium carbonate.

Chemically you could use an acid to remove the CaCO3, or a stronger acid to remove some of the surface. This is not a do-it-yourself operation.

Another approach would be to use a polishing abrasive, like rouge or ceria, to remove enough of the surface to bring back a smooth surface. Probably best done with a hand-held drill and a polishing disc, with the abrasive. A specialist would get a better result than DIY.

Try CLR or Lime Away in case it's a calcium deposit. Available at hardware stores. m

Thanks Terry and Michele, I'll try some CLR first. If that doesn't work, I'll take it to a pro. Thanks again, Kerry