Can food remnants, like stains, make you fleishig/milchig?
For example, if I had a steak and got it on my sleeve, then the next day wiped my mouth with that sleev,e can I become fleishig from that? Another recurring instance is that I'll be eating and I'll have some grease on my hand, and I'll say Birkat Hamazon on my phone. Then later, I'll touch/use my phone, and then unintentionally touch my mouth or what not. Is the grease/remnants that are on the phone liable to make me fleishig/milchig?
Include sources if possible.