crockpots

Question

Re. the message to Yehuda about crockpots. Are you referring to a glazed pottery (china-like) pot that would not need Haagalah for use on Pesach since it's not Bolei'ah? For that matter, How about using year-round china w/o Kashering it? (If not, can it be kashered?) Or were you referring to a metal pot that has a protective coating (such as Teflon)? Thanks