I accidentally warmed up dairy food in my meat microwave. How do I kasher my microwave?
Wait and don’t use the microwave for 24 hours. Then clean it and the glass dish well so that there I no residue of meat left in the dish walls etc. Place a bowl of water in the microwave until it boils, then open the microwave, move the bowl to the side and boil again (this is to kasher the area where the bowl was sitting).
Halachos of Pesach ( R’ Eider zt”l ) pg. 182, in the name of R Moshe Feinstein zt”, Lehoros Nosan 7- 61 (5), Shvus Yitzchok 6 chap. 5, in the name of R’ Eliyashiv zt”l ( only regarding mixtures of meat and milk), Tshuvos V’hanhagos 2-212, M’bais Halevi 14 pg. 23 (12).