How does one Kosher a pot or pan that became forbidden due to Basar Bechalav?

Earthenware and other non-Kosherable material All vessels made of earthenware, or other non-Kosherable materials, can only be Koshered through placing it in an oven and heating it to the point that it can be reformed [i.e. Kivshan].^[1] [This is in contrast to an earthenware oven which can be Kashered through Libun Gamur.^[2]]

Kosherable material: All vessels made from Kosherable materials only require Hagala even if they absorbed meat or dairy without liquid.^[3] [Thus, if one baked meat in a dairy baking pan, the pan only requires Hagala.^[4]] This, however, only applies in the case that the dairy vessel had meat cooked in it or vice versa, however, if one cooked actual meat and dairy together in the vessel, then Libun Chamur is required in all cases that the food was roasted/baked without liquid.^[5]

[1] Admur 451:9

Additional points and law of self-clean oven:

1. Biblically, Keli Cheres is Kashered through Libun Chamur/Gamur, if it is done to the inside.
2. Rabbinically, some Keli Cheres need a Kivshan Malei Eish if it is not filled with fire on the inside as its cooking style, so a typical earthenware pot needs a Kivshan, while an oven of back then needs plain libun.
3. From above it is clear that Halachically, Libun and Kivshan are not the same heat.
4. The original case in discussion in the Poskim regarding switching meat to milk is dealing with an oven, of which libun works, and today the custom is to use self cleaning. A self cleaning oven is viewed as Libun Chamur and hence can Kasher an oven requiring Libun.
5. Possibly self cleaning would work for all Keli Cheres as the Chashash of Shema Chayis Allayhu is not relevant, and hence even if we view it as libun it would be ok, and possibly it can be viewed as a Kivshan.
6. Many Poskim hold that the Chashash of Shema Chayis is only by expensive earthenware, and not by cheap.
7. Bottom line, it is possible that even cookware Keli Cheres can be Kashered through self clean, and certainly if it is cheap keli cheres.

[2] Admur 451:6-7; 461:1; 494:16

[3] Admur 451:13 in gloss; 1^st approach in Shach 121:7; unlike 2^nd approach in Shach ibid, based on ruling of Ramaz, 96 that requires Libun Chamur even by Basar Bechalav if it absorbed meat or dairy directly without liquid; See Pesakim Uteshuvos 121:7; See also Hakashrus 1:37 and footnote 67 who writes that baking pans cannot be Koshered at all, as they require Libun Chamur. Based on above, however, this is inaccurate, as Hagala suffices in the scenario that one simply cooked meat in it after cooking milk or vice versa.

[4] See previous footnote from Hakashrus ibid

[5] See Admur ibid