Dear Rabbi Simon
I am aware that it is possible to kasher an urn – we found your very helpful instructions on the Ask the Rabbi page on the Kesher website.
1. Does it only refer to metal urns? Or does it include the common “white” ones that most people have?
2. Is it possible to kasher a slow cooker for Pesach? And if so, how?
Thank you very much
Your plastic urn may be kashered in the normal way.
Slow cooker is not realistic to render suitable for Pesach use, as the container for the food itself is porcelain which we do not kasher. If you were able to source the porcelain pot (insert) separately the heating unit may be usable, however I am not sure how practical this is. Best to buy a separate Pesach slow cooker for use year by year. A quick search online reveals that they are not very expensive.
Rabbi Rashi Simon