As I understand it silver would gradually work its way into the hands of guardsmen via payment for duties. As a result of this it would then work its way into the wider Covian community (and the roleplay community as a whole) via its use to pay for goods and services that you would normally use gold to pay for.
And for the record Alf, if a mongbat was lucky enough to best you in combat they would naturally become a hero to their kin.
But that'll never happen, you're Alf, you cannot be killed.