http://revach.net/article.php?id=798

Section: Halacha   Category: Tshuvos
Sridei Aish: Can You Kasher Plastic Utensil?

Plastic utensils that were used for non-kosher food items, if it was used while the food was hot it requires Hagalah (immersion in boiling water). Even though according to the Remah glass utensils that were used for hot food can't be kashered, however the Acharonim are lenient regarding plastic utensils and it is permissible once it is kashered. (Sridei Aish OC #46)