Tovel a washing cup?

Hi,

If there is a chance that one might use a netilat yadayim (ritual hand-washing) cup to hold a beverage for drinking, then assuming it is made of a material which requires immersion, one should immerse it in a mikvah, as one does with utensils that will be used for food. One should immerse it along with a utensil that definitely requires immersion, since it is unclear that immersing the netilat yadayim cup would warrant a blessing.

(Rivivot Ephraim 1:122)

המצפה לישועה,
Mordechai