This one works just as RS gold Prospector Jacket that was in the pack preceding. Also, while wearing it, you are able to mine 2 ores at same time (at 10% chance) while mining, which greatly boosts the exp gain. You can obtain this item by completing Varrock Diary - easiest, medium-hard and elite.
Elite Clue Scrolls - Things get even more complicated when it concerns Clue Scrolls of this tier. Another of the more efficient methods to farm these scrolls is Barrows. Barrows is a profitable minigame on its own, therefore if you want to farm Clue Scrolls there, you could earn some additional money prior to even beginning Treasure Trail. There's three percent of the chance to be awarded a scroll when you defeat all six of Barrows brothers.
Master Clue Scrolls - Although Master Clues may be the most difficult to complete but they're not so difficult to get. There are currently two ways to acquire these within old school RuneScape. One method is to finish easy Clues. Master Clues can be obtained from the Reward Casket. If you play on Easy Difficulty, it is 1/50 chance, on Medium 1/30, on Hard 1/15 and Elite 1/5. Thus, the buy Runescape gold only Clue Scroll that does not have an Grandmaster Clue Scroll as the reward is for beginners.