The status of Pareve foods cooked in a clean Ben Yomo meat pot or vice versa:
Some Poskim rule that a Pareve non-Charif food [whether dry or with gravy] which was cooked or roasted in a clean meat pot, remains Pareve and is permitted to be eaten with milk products, even if the pot was Ben Yom. Other Poskim rule that a Pareve food which was roasted or cooked in a clean Ben Yomo meat pot, is forbidden to be eaten with milk products, even if the food is not sharp. Practically, the custom [of Ashkenazim] is like this opinion and to initially prohibit eating or cooking such food with milk products. However, Bedieved, if one already cooked it with milk products, the mixture is permitted [even if the food does not contain 60x]. [This applies whether the Pareve food was roasted or cooked in the meat pot.] Nonetheless, the food may even initially be eaten [and cooked] with dairy utensils, even if the pot was Ben Yomo. [The same applies vice versa. This applies even according to the stringent opinion above.] However, one may not initially pour the hot Pareve food directly from the meat pot onto a milk utensil, rather a second utensil is to be used to transfer the food from the meat pot into the milk utensil.
If one cooked Pareve food in a dairy pot then if the pot is Ben Yomo or one cooked a Davar Charif in the pot [in a way that is defined as a Davar Charif as explained above], such as onions or garlic, or the pot was dirty with dairy residue, then it is forbidden to eat the food together with meat. Nevertheless, one may eat the food on meat vessels if the pot was clean and the food is not defined as a Davar Charif. Likewise, one may eat the food during a meat meal. If the pot is clean, not Ben Yomo and does not include a Davar Charif, one may eat it together with meat.
 95:1-2; See Chulin 111b; Beis Yosef 95 and Aruch Hashulchan 95:1-14 for all the opinions in Rishonim
 Michaber 95:1; Rambam Machalos Assuros 9:23; Rashi, brought in Tur 95:1 [unlike understanding of Rivan]; Rabbeinu Tam; Riy Hazakein; Sefer Hateruma 61, and Rosh Chulin Kol Habasar 29, brought in Tur ibid regarding cooking [as opposed to roasting]
According to the Michaber, may one initially cook Pareve foods in a meat vessel in order to eat with Milk? Even according to the Michaber, it is initially forbidden to cook Pareve food in a Ben Yomo meat pot with intention to eat that Pareve food with dairy products. [Admur 494:16; Shach 95:3; Taz 95:4; Rabbeinu Yerucham 15:28, brought [and negated] in Beis Yosef 95:1 in Bedek Habayis; Semak 213 and 198, brought in Beis Yosef ibid; Peri Chadash 95:1; Minchas Kohen 1:12; Lechem Hapanim 95:3; Beis Lechem Yehuda 95:3; Kreisi 95:1; Erech Hashulchan 95:5; Kehilas Yehuda 95:1; Zivcheiy Tzedek 95:2; Ben Ish Chaiy Korach 13; Kaf Hachaim 95:1 and 21 that the Michaber ibid retracted from his ruling in the Beis Yosef which was written before his Shulchan Aruch [see Yad Melachi 15; Chida in Shem Hagedolim Sefarim 75], and therefore the ruling in Michaber ibid is written in the form of Bedieved; Rav Shalom Mashash in Mizrach Shemesh 95 and Shemesh Umagen 1:8; 2:42] Thus, one may not heat water in a Ben Yomo meat pot for the sake of kneading dough, as one often eats bread with dairy. [Devar Moshe Y.D. 9; Shulchan Gavoa 1; Zivcheiy Tzedek 95:3; Kaf Hachaim 95:2] The same applies vice versa. However, some Poskim rule that according to the Michaber it is permitted to even initially cook Pareve foods in Ben Yomo meat pot with intent to eat with dairy. [Beis Yosef 95:1 in Bedek Habayis, printed and his commentary on the Tur, writes that one may even initially cook in the Ben Yomo pot with intent to eat with the opposite food [However, the Poskim ibid say the Beis Yosef retracted this ruling in his Shulchan Aruch and rules that it is only allowed Bedieved.]; Maharah Even Tava in Shut Tashbatz Chut Hameshulash, Hatur Hasheleshi 33; Beis David 42; Pnei David Papau 2; Beis Yehuda 2:92; Yabia Omer 4:4; 94; Rav Yitzchak Yosef] Even according to the first approach, if one already cooked the Pareve food in a Ben Yomo meat pot with intent to eat with dairy, he may go ahead and eat it with dairy. [Peri Chadash 95:1; Lechem Hapanim 95:3; Kreisi 95:1; Kehilas Yehuda 95:1; Zivcheiy Tzedek 95:5; Kaf Hachaim 95:5 unlike Minchas Kohen 1:12]
 Issur Viheter 34:1; Kneses Hagedola 95:2; Beis Lechem Yehuda 95:2; Kaf Hachaim 95:7
 See Tur 95 and Beis Yosef 95:1 for opinions in Rishonim [Sefer Hateruma 61; Semak 213; Semag 140-141] who differentiate between cooked and roasted and rule that we permit only cooked foods and not roasted foods, as by cooked there are three Nat Bar Nat, while by roasted there are only two. However, the Beis Yosef ibid concludes that Lehalacha it is implied from the other Rishonim [Rambam; Rashi; Tosafus] that there is no difference at all, and so he rules here in the Shulchan Aruch.
 A pot is assumed to be cleaned from any meat residue unless one knows for certain that it was not cleaned well. [Shach ibid]
 The reason and explanation: The meat taste that the Pareve food contains has traveled from the meat to the pot and then from the pot to the Pareve food. This is called Nat Bar Nat Dihetera. The reason that this meat taste is not considered problematic with dairy is because the meat taste which the Pareve food absorbed from the Ben Yomo pot is so indirect and diluted that it does not have sufficient intensity to merge with milk and cause a fusion of Basar Bechalav. [Taz 95:1; Kneses Hagedola 95:24 in name of many Poskim; Peri Chadash 95:3; Lechem Hapanim 95:2; Chochmas Adam 48:17; Zivcheiy Tzedek 95:15; Kaf Hachaim 95:8]
 Opinion in Rama 95:2; Rivan in name of Rashi; Issur Viheter Aruch Klal 34 [brought in Darkei Moshe 95:1]; Mordechai; Or Zarua; Rabbeinu Yerucham 15:28, brought in Beis Yosef [Bedek Habayis 95:1]; Shach 95:3; Peri Chadash 95:4; Lechem Hapanim 95:4; Beis Lechem Yehuda 95:3; Kreisi 95:4
 The reason: The reason for why the Rama is stringent is because the Rama rules Nat Bar Nat Dihetera is initially forbidden.
 Kaf Hachaim 95:21; However, the custom of the Sefaradim is like the opinion of Michaber
 Rama ibid; Semak; Issur Viheter; Peri Chadash 95:5; Lechem Hapanim 95:6
Ruling of Admur: Admur in 494:16 rules that if one used a meat/dairy vessel [i.e. Marda] to remove bread from an oven then nevertheless the food remains Pareve and may be eaten with milk/meat, as it is Nat Bar Nat Dihetera, as explained in chapters 94 and 95. Vetzaruch Iyun, as here the Rama rules that it is forbidden to eat such food with meat as we hold that Nat Bar Nat is initially forbidden. Several suggestions have been offered into how to understand Admur: 1) Perhaps Admur’s case is an exception as when bread is placed on a meat/dairy vessel it is only penetrated a Kelipa’s worth. 2) The Rama ibid is only stringent by food that was cooked in a vessel, while Admur is referring to a vessel that contacted a food, which has a more lenient status as explained in Rama 95:2, brought in Halacha 4. 3) Perhaps Admur rules, unlike Shach, that even if both the food and vessel are hot, the food remains Pareve. 4) Perhaps Admur is referring to the letter of the law of why a decree should not be made to require one to use a Pareve Marda to remove the bread. [See Shaareiy Yoreh Deah p. 317; Piskeiy Admur Hazakein p. 194; Hearos Ubiurim Ohalei Torah 655 p. 25]
 Rama ibid; Semak; Aruch; Taz 95:4 that one who is lenient like the Rama has not lost out; Admur 494:16 [that we only suspect for Nat Bar Nat Lechtachila]; Peri Chadash 95:5; Lechem Hapanim 95:6
Other opinions: Some Poskim rule that Pareve food which was roasted in a Ben Yomo meat pot, is forbidden to be eaten with milk products and even Bedieved the mixture is forbidden unless there is 60x versus in the milk versus the food. [Rashal Issur Viheter Shelo on Shaareiy Dura; Yam Shel Shlomo Kol Habsar 63, brought in Shach 95:4; Beis Lechem Yehuda 95:4 in name of Poskim; Kaf Hachaim 95:22 concludes that one who is stringent like the Rashal in a case that does not involve a great loss, is blessed.] The above Poskim are only stringent regarding a roasted food. However, a food that is cooked in liquid inside of a meat pot, or a food that is roasted in a meat pot that is Ben Yomo from meat that was cooked in liquid, is permitted Bedieved if it became mixed with dairy. [Chavas Daas 95:5; Pischeiy Teshuvah 95:4; Kaf Hachaim 95:2]
 Peri Chadash 95:5; Lechem Hapanim 95:6; See opinions in Beis Yosef 95:1
 Rama ibid; Taz 95:5; Semak 213; Semag 140-141; Lechem Hapanim 95:8; Biur Hagra 95:8; See Chulin 111b that fish that were placed on a meat plate may be eaten with dairy, and this applies according to all opinions
May one even initially cook in a meat pot with intent to eat with a dairy vessel: Some Poskim rule one may even initially cook Pareve food in a Ben Yomo meat pot with intent to eat the food with milk utensils. [Peri Chadash 95:5; Lechem Hapanim 95:9] Other Poskim, however, rule it is forbidden to do so unless it is a time of need. [P”M 95 M”Z 5; See Kaf Hachaim 95:26; Chochmas Adam 48:2; Shaareiy Yoreh Deah] See Beis Yosef 95:1
Other opinions: Some Poskim rule that Pareve food which was roasted in a Ben Yomo meat pot, is initially forbidden to be eaten with milk utensils. [Taz 95:4 in understanding of Rashal ibid]
 Kaf Hachaim 95:24
 Shach 95:5 based on Rama 95:3; Kaf Hachaim 95:27
 Hakashrus 10:94