The Bais Yosef (Y.D. 121) quotes the Orchas Chaim who
“The same way you need to Kasher a vessel that has absorbed Issur , so too must you Kasher a vessel that absorbed Dovor Ma’us (repulsive) like urine etc. You should not be Meikel on this Minhag”
The Bais Yosef argues. He holds this Minhag has no source and nobody follows it. He says:
“All you need to do, is rinse clean the vessel and may use it without Kashering."
I saw or heard (don’t remember, where/who) an explanation on the Machlokeh, is if the Issur of Ba’al Teshaktzku is an Issur Gavra or Cheftza.
The Orchas Chaim holds it is an Issur Cheftza, therefore, when it is absorbed in a Keli it is no different than any other Issur and needs Kashering.
The Bais Yosef holds Ba’al Teshatzku is an Issur Gavra,
Therefore all you need to do is to clean it.