I had chicken in a pyrex fridge. A yogurt spilt in the fridge.
I put the pyrex dish with chicken in the oven and cooked it. Afterwards I realized that inside the oven was bits of the yogurt. I assume I have now made the oven and pyrex dish treif.
My question is, I know I can kasher my over, but is there anything to do about the pyrex dish, or do I have to simply throw it out?
The Sefardi minhag is that it doesn’t need koshering. However, regarding he Ashkenazi minhag, there is controversy about this. The Rema regarding Pesach says that we glass cannot be koshered. Regarding Basar B’chalav there is controversy among the poskim. Numerous poskim say that it doesn’t need koshering at all, however some say that it should be koshered (preferably 3 times), and others say that it cannot be koshered.
From reading your question it sounds like there was a little bit of yogurt on the outside or the bottom of the dish, and that you used the dish for cooking the chicken. This being the case, even the poskim who are stringent regarding glass, would say that since the amount of yogurt was minimal, it was botil between the dish chicken and water inside the dish. In that case there would be no need for you to kasher the dish at all.