Bismillah

Al-jawab billahi at-taufeeq (the answer with Allah's guidance)



The vomit that is full mouth will be considered Najis (impure). (Shaami vol.1 pg.266)

If this is equal to a Dirham, which is the circumference of the inner hollow of the palm then it is Wajib (necessary) to wash this from your garments. If it is less than this amount then it will be Mustahab (preferable).

However, if one forgets this then Salah performed in such clothing will be valid.
(Quduri Pg. 24, Nurul Idhah Pg.53, Hashiyat Tahtawi Pg.157, Ahsanul Fataawa Vol.2 Pg.89)

If it is more than a Dirham then it is Fardh to remove it and Salah with this amount will be invalid. (Quduri Pg. 24, Hashiyat Tahtawi Pg.157)



And Only Allah Ta'ala Knows Best.