Does the appearance of a yellow color on undergarments necessitate their purification for prayer, and does the persistence of the color of impurity after washing indicate that they are not pure?

The ruling on one who finds a trace on their clothes and doubts whether it is manī (seminal fluid) or madhī (pre-seminal fluid) has been detailed previously. As for the clothes, their ruling follows the ruling of the trace found on them. If it is not manī (like madhī, which is yellowish), then it is not permissible to pray in them before washing them. As for the color of the impurity, it must be removed if possible; otherwise, it is excused.