Completion of each stage of the Seer’s Village Achievement Diary will allow you to store greater amounts of coal in the trucks — up to after completing the hard Seers Tasks. After completing at least 1 quest in the Recipe for Disaster quest, you can access this chest, however it is recommended to have all of the quest completed for most profit. Sell at the Grand Exchange. Grimy herbs will give you more profit, but will take quite a bit longer. Morytania Hard Diary. Make sure the 50th task is the absolute hardest one because for the 50th task, you get 15 times the amount of points you would have! Preferably anything above toadflax can make you a decent profit.