NSS & OSS New Sheepskin Scrolls & Old Sheepskin Scroll are two kinds of scrolls that provide you with a Pirate treasure map, there are multiple desirable drops from these including Level 75 Equipment, Ref Gems, Goddess's Favor, and with some luck, players can even find Unique Gems in these, except for Gem of Soul
NSS  ( for players from lv15-100 )
 ----->   0 - 200000 Unique Gems Normal Gems Kraken Coin  
OSS
 ----->     0 - 20000 Unique Gems Normal Gems  Kraken Coin  75 Rare Items   OSS can only be purchased from other players or farmed by opening Fortune Lots, these lots can be purchased from other players or at Spring Town after completing the Language Barrier Quest. If you are considering opening Fortune Lots, I recommend you hand all of your money to a second account prior to doing so, as Fortune Lots will make you lose money in the long run. TIP: Fortune Lots can also grant Drop Rate x 2 (Same as a Charmed Berry) for a length going anywhere from 1 to 150 minutes, you can use them to get Drop Rate x 2 when you need to farm while also getting OSS at the same time. When you are ready to begin hunting for OSS, you can start by double-clicking it, unlike the NSS, this you can do at any location. After double clicking it, you will be provided with a map and coordinates in the system, the coordinates will be for a place in Magical Ocean (Shaitan City), Ascaron (Argent), or Deep Blue (Icicle). When you arrive to the OSS location, you can loot the treasure by double clicking it.
Recommended tickets to have in handy, this will help speed up the process: Abandon Mine 1
Andes Forest Heaven
Lone Tower 1
Thundoria Harbor
Thundoria Castle
Icespire
Oasis Heaven
Barren Cavern
Sacred Snow Mountain Tickets (This are optional as they are obviously more expensive, you can get away with Thundoria Harbor tickets but this would speed up the process in some cases)