I had my iPhone into a shop for repairing when my power button failed. After I got it back, I have very bad bluetooth reception and almost non-existent WiFi. I remember that the shop did not use gloves. I took it back there and they are denying all responsibility.
So I assume that there's probably some finger oil on various parts and I've seen all of the suggestions on here about cleaning "all contacts" with a degreaser or Windex. But I don't know what "all contacts" are. Can someone help me out and point them out?