That's as a result of oil barrier. I like that idea, would like I'd considered it!! Having said that, that may be, I now 3D print cat food bowls which have an exceptionally little, canted inward oil ring, which prevents kittie's fur from accidentaly getting oily. It works really well https://pet-shop-dubai02221.blogripley.com/37095274/pet-shop-online-fundamentals-explained