Garudapurana 2.5.21

2.5.21

prathame 'hani yaddravyaṃ tadeva syāddaśāhikam /
yāvadāśaucamekaikasyāñjalerdānamucyate //

Whatever substance [is used] on the first day should be used for the ten days. / An offering of a single handful of water is prescribed for as long as the impurity lasts;