Sinco Doar is one of the archeologists in the Varrock Museum in Varrock. Though he can be seen in free worlds, players can not actually talk to him unless they are on a member server.
The player may show him items that have been discovered while cleaning uncleaned finds in the Varrock museum. If he finds the item interesting he will ask the player to put in one of the display cases. He will also pay 5 coins for all jewellery offered.