If one is certain that the remains of urine came out after walking and it
soiled the clothing, the subsequent Wudhu will be valid, but merely making
Wudhu does not make the clothing Taahir (pure). The soiled portion of the
clothing will remain impure and must be washed in order for Salaat to be
valid as Salaat with impurity on clothes is not valid.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai