Source: medlem
Picking up Dragon Scales and sell it for more RS gold
Blue Dragon Scales can be ground and turn it into Blue Dragon Dust using pestle and mortar. The Dragon Scale Dust is a secondary ingredient to create weapon poison and anti-fire potions which is pretty useful when fighting powerful dragons and a good source to make more RS gold.
In this guide you can farm a ton of Blue Dragon Scale and to be able to make more RS gold in just an hour just by walking around the dungeon and picking the scales. You only need 70 agility and 60 dungeoneering to be able to quickly gather a lot of Dragon Scale.
Before you start, it is best to have a Beast of Burden like War Tortoise so that you can carry more stuff and also it can increase your storage capacity and store a lot of Dragon Scales. That means you can have more RS gold when you sell all those scales.
Go to the Taverly Dungeon from the northwest of Falador. Squeeze through the Obstacle Pipe to your right side. You can summon your Beast of Burden now. There will be Blue Dragon scale in the area but you can skip this area as we can go to a much better spot to pick up a lot of Blue Dragon scale to sell RS gold.
Enter the Mysterious Entrance to the north and to the left from where you enter the room. There will be a rocky wall in the middle of west side. Around it, there will be a lot of Blue Dragon scales scattered around. Pick them up as much as possible until your inventory is full since the scales will respawn in a short time. Now sell all your Blue dragon scale to make RS gold or grind them to make Dragon scale dust.