Can Pyrex mixing bowls be used for both meat and dairy preparation? (Not at the same time obviously, but washed in between.) I'm not referring to the Pyrex baking pans which would be kli rishon and cannot be used for both, but rather the prep bowls to mix ingredients in.
While you should check with your own local authority, this site (the Star K) makes the following two statements from which you could draw an inference:
a. Q: There are many varieties of glass on the market. Do arcoroc, duralex, pyrex, corelle and crystal have the halachic status of glass?
A: Yes, they do.
b. Q: Can other glass dishes, such as salad bowls or casseroles, be used for both dairy and meat meals?
A: If the food is cold, or the glass dish is used as a Kli Sheini, it may be used for both dairy and meat meals. Unless it is used on the oven or range, a Kli Sheini is okay.