How do I clean an opalescent vase?

Wash the glass gently in warm, soapy water using a soft cloth to protect the delicate surface texture. Avoid harsh chemical cleaners and abrasive scourers that can damage the frosted or stained highlights. Dry the vessel thoroughly with a lint-free cloth to prevent water spots from dulling the opalescent finish. Take extra care around the moulded relief areas where dust and residue tend to accumulate.

What is the difference between pressed and blown glass?

Pressed glass is formed mechanically by forcing molten material into a metal mould with a plunger, which results in thick walls and sharp exterior patterns. Blown glass is shaped using a blowpipe and breath, creating thinner walls and smoother interior contours. You can often identify pressed items by the presence of mould seams and exceptionally crisp, high-relief exterior decoration. Blown pieces generally show pontil marks on the base rather than the pressed distribution of material.

How can I date a Victorian celery vase?

Victorian celery vessels from the mid-nineteenth century typically feature heavy flint glass construction with deep vertical ribbing or panel cuts. They were designed specifically to stand upright on dining tables to hold stalks of celery in iced water. Look for the characteristic weight, soft greyish refraction of older flint glass, and hand-finished pontil scars on the underside. These physical traits distinguish authentic nineteenth-century examples from later commemorative reproductions.