Which is due to oil barrier. I like That concept, desire I'd considered it!! However, that may be, I now 3D print cat food bowls which have a very modest, canted inward oil ring, which helps prevent kittie's fur from accidentaly getting oily. It works rather well and is simple https://dominicknakvf.activoblog.com/41372313/the-2-minute-rule-for-pet-toys