Recently had my son-in-law say he had quite a few moisture reports on an S8+. He was using USB-C cable charging.

I had a look in the botton of the socket with a jewellers loupe and could see stuff in the base of the socket.

Tried to blow it out with compressed air... no luck.

Carefully used a fine dental probe to lift out considerable impacted dust in the base of the socket.

I could then see the shiny base of the socket.

Gave the socket a quick spray with and IP alcohol aerosol and a further blow out with the compressed air.

Fitted a USB dust plug and set him up with a wireless charger.

No further moisture reports in the last few weeks.