- Glassware is different than metalware
Even though glass is similar to metal in as much as it can be melted down and refashioned, it’s dissimilar in the following way:
• Metalware which is tamei, when broken down becomes tahor. When it is refashioned into a new vessel, the Rabbis decreed that it reverts to its old status of tumah.
• Glassware , which is tamei, when broken down also becomes tahor, but when its remade into a new vessel, it does not revert to its old tumah. The reason is that since the tumah of glassware is only Rabbinic, we do not impose the law of the restoration of an old tumah which is also only Rabbinic.
- Glassware’s transparency
Rav Ashi is of the opinion that glassware has the halachos of tumah as earthenware and not metalware. The Gemara asks that if glassware has the same halachos of tumah as earthenware, why then does it contract tumah when it is touched by something tamei on its outer surface, whereas earthenware only becomes tamei when a tamei object goes inside of it?
The Gemara answers that being that the transparency of the glass enables one to see the interior of the glass from the outside, it in effect makes the outside surface of the vessel equivalent to the inner cavity. Therefore when something which is tamei touches the outer surface it is as if it is within the inside of the vessel and the vessel becomes tamei as a result.
- Reason for instituting that old tumah status reverts to metalware
The reason the Rabbis enacted a decree that tamei metalware that became tahor through breakage, should revert to its old tumah status when refashioned was as follows:
Midoraysa, a metal vessel that became tamei through contact with a corpse, (or being in the same enclosed space as a corpse), requires a week-long purification process which includes sprinkling of the mei chatas (waters containing the ashes of a parah adumah) on the third and seventh day, as well as immersion in a mikveh on the seventh day.
One way to expedite the purification process is to break the tamei vessel, which renders it tahor, and then repair it. (Piercing a hole in the vessel as well, would be sufficient to consider it broken).
The Rabbis feared that as a result of this loophole, the institution of mei chatas would fall into disuse, so they decreed that the old tumah status would return when the vessel was repaired.
- Queen Shaltzion tried to use this break-and- repair method at her son’s chasuna when the utensils were tamei, but the Rabbonim told her the old tumah status returned).
