Plastic ware

Question

Are reusable plastic cups and bowls usable on Pesah -- i.e., like glass? Does it matter whether they are clear? None is used for cooking. (I am thinking of children's cups and bowls for soup, cereal, oatmeal, etc.) Also, I understand that Pyrex, so long as clean, is usable on Pesah. Is that correct? Many thanks for your continuing service through this site. Hag Kasher V'sameah.