I accidentally heated fleishig food (chicken fingers) on a milchig Corelle dish in the microwave. What is the status of dish?
According to the sefardi minhag it doesn’t have to be kashered, but according to the ashkenazi minhag it may and should be kashered. Wait 24 hrs. and then heat up a pot of water until it is boiling well, and insert the dish when it is clean.
See the following link where this issue was discussed http://dinonline.org/2017/01/05/kashrut-of-glass-plates/.
Although in the other cases discussed in the link, there are poskim who say that if the glass absorbed trief through kli roshon, that it can’t be kashered, however here there are a number of factor to make it more lenient. First of all when heating food in a microwave, there aren’t walls to help make the food or the dish hot, rather the food itself that got heated would be the heat sources that heated up the plate. The chicken fingers are only minimally moist, and therefore the amount of absorbed taste going into the glass plate is minimal and only k’dai klipa. Besides, it isn’t clear that the glass plate indeed got hot, because the plate only gets hot later; therefore it is only a safek if it got hot from the food. Coupled with the machlokes if we say that glass may not be kashered, we can rule that according to everyone it may be kashered, even for ashkenazim.
R’ Y. Cahen shlit”a