LG G3 Invalid Sim Card

The LG G3 Invalid Sim card message happen to me and I got a replacement LG G3 phone and I am sorry to say after about a year it is happening with the replacement phone too! I bought a new battery thinking maybe it was a heat issue with the battery as the phone did seem hotter than normal on the back side. That didn't seem to fix things so I spent some time looking at the SIM cage once again. Well as luck would have it, I took my case apart on the G3 and noticed there was a slight white buildup (specs of white) on the back end of the sim card cage. (Kind of the consistency I am thinking on car battery connectors, which I am wondering if it is actually something along those lines) I scraped that out and blew on it as well. I also tried to bend up the pins at the from of the sim cage with a pin. Be careful!!!! Seems to be working fine (this has happened to me before though so time will tell) but the big difference is it is stone cold where I could see over time it would heat up and the issue would return. I am not sure if this is going to be a fix for this but it seems promising at this point. I definitely wanted to let folks know. Hope this helps someone!!!!