I saw an article a while back that said that many of the major slow cookers had interior pots whose glaze contained enough lead to be a concern. There has been a lot written since that time. Here is a link to a recent article about lead in the cookers:
Be sure that yours does not contain lead, especially if it is an old pot. Mine was one that contained lead so now I use it as a hot water bath to heat beeswax for candle dipping....
ds born 11.20.09 from single embie
highest fsh 75