I poured boiling water from a kettle into a cup containing coffee (no milk).
Before pouring the water into the cup, I washed off the cup and thought it was clean.
However, after I poured the water I found a small spot of coffee on the rim of the cup.
My question is, when I poured the water, the hot water hit the rim of the cup, and if the coffee spot was from a previous user it may have contained milk and so it might be a possible problem of zeiah (the kettle was right on top of the cup).
On the other hand, it could be that the coffee spot was from coffee that splashed out now when I was pouring the water. And maybe the hot water didn’t hit that exact spot (not sure if that makes a difference).
(Also, the night before I used a cup and had coffee with pareve milk so maybe even if the spot was there previously it was pareve milk.
But I’m not sure if I used that same cup).
Is there any problem with the kettle or does it still remain pareve?
Everything is fine. Even if the coffee spot did have milk in it, it is bolit to the water that was poured from the kettle, and did not make anything milchig.