About 15 yrs ago we moved to a different country and left our things in storage for around 7 years. Nothing was used. When we finally received our household items, some of the pyrex baking pans were mixed up and I could not recall if some of them were used for milchig or fleishig. The ones I was sure about I separated immediately. But there were some that I thought were fleishig and used them as such. But now I am wondering if that was okay. Or do I have to throw them out because I am not 100% sure? What about the status of my kitchen in general? Would this be any kashrus problem? And is pyrex in general a problem?
Answer:Pyrex in general has the same status as glass, concerning which there is a dispute between Shulchan Aruch and Rema. According to Shulchan Aruch, glass does not absorb, and may be used for both milky and meaty; according to Rema, glass may not be used for both milky and meaty. Although Ashkenazim follow the ruling of Rema, there is certain room for leniency under extenuating circumstances. This is true is your case, in particular because you believe that the dishes were used for meaty, and it is permitted to continue to use the Pyrex pans for meaty dishes. However, dishes concerning which you have true doubt must be kashered by means of hagalas keilim three times (fully immerse the pans in boiling water), which is possible with regard to Pyrex dishes (but not for glass dishes).
The kitchen is in any event unaffected, because the age of the pans ensures that anything they might have absorbed cannot affect anything else.
Sources: Shulchan Aruch, Orach Chaim, 451:26 ; Or Zaruah 2:256; Tzitz Eliezer 9:26 (hagalas keilim may be performed for Pyrex dishes); Minchas Yitzchak 1:86 (Pyrex dishes may be kashered)