Sim card not working

[Jayjayuno]

Phone got wet. Dried it out, dried sim card. Now it's not working on galaxy s21

[MI5 · Accepted solution]

@Jayjayuno 

Pop into your local O2 store with photo ID or call 0344 809 0202, 0800 902 0217 or 0800 032 1402
You can use Skype to call if no other phone. Guide: A Guide to Skype 
Call 202 from your O2 mobile or 0344 809 0202, 0800 902 0217 or 0800 032 1402
When it comes to the reason you are calling, stay silent for 15 seconds and you will be taken to the keypad options.
Press 2 for Everything Else
Press 5 for More Options
Press 7 for Anything Else which will put you though to someone.
Say 'Upgrade', 'Lost/Stolen', or 'Fraud' if the suggestion above doesn't get you through.
Best time to call is 8 am.
You can also reach O2 via social media:
Facebook (https://o2uk.co/O2CFB), Twitter (https://o2uk.co/O2CTW), or Instagram (https://o2uk.co/O2CIG)

[Jayjayuno]

I did pop into o2 and they replaced the sim card. It then worked for several hours, then failed again for a while, now is in working mode.

I am left with the insecurity that it might fail again at any time, in an embarrassing situation, like trying to pay for something.

Is there a way of cleaning the inside of the phone where the sim card fits? Trying to avoid an expensive repair job on the phone.

[MI5]

@Jayjayuno 

The problem is that water damage is usually terminal.

You would need to strip the phone down completely to remove all oxidation left behind after the water dried out but it's a job for the experienced with no guarantee of success.