Our son mistakenly took a glass from a closed cupboard that should not have been opened during Pesach and used it to make lemonade. The glass was clean, but not kashered for Pesach (we are Ashkenazi).
Is the lemonade he made kosher for Pesach? What else do we need to know about what to do with this glass now?
If everything was made with cold liquids [and did not sit for 24 hours], the lemonade is kosher for use. The glass should be returned to the cabinet it was taken from.