Hi! I have two of the exact same pan. One was meat and one was dairy. But now I have forgotten which one is which. The pan is metal. What should I do?
You will have to kasher both pans in order to you them. You need to clean both of them well, and get off any baked on grime, rust, grease. If there are any seams, like between the pan and the handle, that should be cleaned out with a tooth pick so that it is clean. Then you can immerse the pan into a pot of boiling water, while the water is bubbling well. then wash the pan off with cold water.
For the future, you should know that the halacha states that we label pots, etc. that look similar, precisely for this reason.
The reason for this is, although pans absorb taste directly from the fire, being that there was no issur in the pans, so libun kal is enough, therefore hagalah will also suffice.