I ran the dishwasher with pyrex glass dishes whose kosher status is unclear to me (I believe the owner used them for both meat and milk – but in the past 6 months or so I’ve only been using them for cold). Does the dishwasher have to be kashered before I can use it for meat dishes?

Thank you for your question.

The dishwasher does not need to be kashered. Since the dishes have not been used for non-kosher food in the last 24 hours, they cannot impart non-kosher taste into the dishwasher.

If the dishes had been used in the past 24 hours for non-kosher food, one should consult a Rabbi if the dishwasher needs to be kashered.