You Can Use any cleaning liquid for this purpose like CTC or any other you prefer. If you are certain that the bad connection is not the reason for your Mobile Phone’s fault, then you can replace the Sim Card Connector, Sim IC with a new one.
Reasons for Problems
It might be due to dust on SIM Jacket contacts.
It might be due to faulty capacitors. If any of them is faulty then it will affect your overall SIM card function.
Issue might also be due to SIM card IC.
Note: Every repairing solution posted here is tested by at least one member of our team. Use the information available here at Your Own Risk. We are not responsible if any harm comes to your device during the repairing process.
Lenovo A319 Sim Card Not Detected Solution, Sim card Ways,Jumper, No Simcard Problem, Sim Card Insert Sim