Believe or not, your next step is mechanic's hand cleaner. Not the ones with abrasives, the ones that have a mineral spirit base.
The most popular and common one is called "Goop". In my city I can buy it in a plastic container in "dollar stores" for $1. One of the other uncommon uses are cleaning your steering wheel, you know, the dark dirty stains that woun't clean off with regular cleaners.
The stains you are talking about are a dry, hardened composite of human finger dirt, and human finger oils, yuk. They are very resistant to spray cleaners. Only cleaners that will merge with, create a solvent action with, and loosen the dirty residue will help you.
Just be gentle, and wipe away the residue and you won't hurt your phone.
The most popular and common one is called "Goop". In my city I can buy it in a plastic container in "dollar stores" for $1. One of the other uncommon uses are cleaning your steering wheel, you know, the dark dirty stains that woun't clean off with regular cleaners.
The stains you are talking about are a dry, hardened composite of human finger dirt, and human finger oils, yuk. They are very resistant to spray cleaners. Only cleaners that will merge with, create a solvent action with, and loosen the dirty residue will help you.
Just be gentle, and wipe away the residue and you won't hurt your phone.