If I have a deep fryer that I use for fleishigs and I made French fries now after not using the deep fryer for a week, am I fleishigs or milichigs?
I am not clear what the case is so I will include various cases. If the oil that was used for deep frying the fleishig was used for the French fries then you are fleishigs. However if the fryer was clean and not used for the week, (even if it wa a little greasy), you may eat milchigs after it, but not together with it.
Y:D 89-2 Shach ibid 19, Chochmas Adom 4-13