I had that issue too. LOL! I still have an unopened sleeve. Went to no pour agar using the dishes linked below and have not had any issues. These are autoclavable and so far have held up. They are not as clear as glass but good enough and reusable.

https://www.amazon.com/gp/product/B077MPZKTM/ref=ppx_yo_dt_b_asin_title_o00_s01?ie=UTF8&psc=1