Practical Ketamim Cases
Nishmat Habayit Teshuva regarding the status of Toilet Paper:
Nishmat Habayit Teshuva regarding the status of liners:
https://www.sefaria.org.il/Nishmat_HaBayit%2C_Part_V%3B_Contraception%2C_Siman_44%3B_Staining_on_a_Panty_Liner_or_Synthetic_Clothing.1?lang=bi&with=all&lang2=en