I found my old Samsung S4 that I lost back in 2014, I had the IMEI blocked and claimed insurance. Is there a possibility that I can get the IMEI unblocked as I can send it to my friend overseas or do I have to give it back to Optus?
As insurance was claimed on it - the device is legally the insurance companies as they paid out on it being lost.
I'd contact Optus and explain you found it and you'd like the EMIE (can never get that acronym right!) unblocked.
Seems to be a standard Optus proceedure
If it was reported lost/stolen and claimed via insurance (assuming it was insurance from Optus) then i dont see why they would unblock it.
If they did then nothing is stopping anyone with insurance saying they lost a device - get paid out for a new one, then "find" the original (insurance fraud).
Best to contact the actual insurance company in this regard.
I'd tend to agree with @Paddylee.
Insurance companies mark all claims with a "Anything salvagable?" section. In the case of a mobile phone this would be no (doubly so for a 4 year old model). A quick call to the insurance company to ask if they want to arrange for it to be picked up will almost certainly result in them saying just keep it.
FWIW I've had a few mobile phones damaged and they have paid to replace the handset. Each time they have no interest in getting the handset.