We can't deny that there are reflexive pronouns in these phrases
Er
wäscht sich.
= He washes himself.
Sie waschen sich.
= They wash themselves.
Er
wäscht sich die Füße.
= He washes his feet.
Sie waschen sich
die Füße.
= They wash their feet.
It is obvious, because the phrases use a construction with sich, which is without a doubt a reflexive pronoun.
But if in the above mentioned phrases reflexive pronouns are used, then it is clear that in the following phrases reflexives are used as well.
It is not to be denied that here we have again reflexive pronouns
Du wäschst
dich. = You wash yourself.
Ich wasche mich.
= I wash myself.
Du
wäschst dir die Füße.
= You wash your feet.
Ich wasche mir die
Füße.
= I wash my feet.
Therefore it is clear that the pronouns dich / euch y mich
/ mir are reflexive pronouns that have been presented as accusative or dative depending on the kind of object. However, leaving aside the theoretical questions you see that it's not too difficult.
