I have a nice heavy baking pan I use for parve baked goods. I had caramelized some nuts in butter and sugar and not having other space, put them on top of a piece of waxed paper on the parve baking pan to cool. When they had cooled, I noticed it looked like the butter had gone through the wax paper onto the pan. Is the pan now dairy?
The pan is dairy because the hot butter leaked on to it, however it is very easy to kasher it. In this case just our boiling water from an urn or pot over the area that was affected and it is fine.
Since the pan was cold and underneath the nuts, therefore although the nuts are hot, they still can only penetrate taste up to a peels worth, as we say ta’ata govar. Iyrui kli rishon will suffice for this. See Y:D 105-3, O:CH 451-5.