Dairy in Meat Dish

Hello Rabbi, if dairy brownies were accidentally baked in a meat Pyrex dish that was clean and had not been used for meat in more than 24 hours and is always washed with soap: A) Can the brownies be eaten? B) How can the Pyrex dish be kashered? Thanks.

A) Yes.
B) Many hold it doesn’t need hechsher since it’s glass, but if you want to be machmir like R’ Belsky and R’ Kamintsky you can’t be machshir it.