I use china rather than stainless steel. I've never had a problem. I wash them when I wash my daily dishes and that has kept my cats happy so far. I put their dry food in a ceramic (china...whatever) serving bowl....and the wet food, at night on flat <------- important too, salad dishes.... then pick them up when they are through and dump 'em in the water in the sink....cat food isn't that awful that I worry about food contamination etc.....with my own eating habits....