In order to lower your entry fee we recommend that you get access to the Ring of Charos (a). Be careful not to use the 'pay' option with it. Blast Furnace foreman since it can void the benefits of the rings. This ring is available at the end of The Creature of RuneScape gold Fenkenstrain questline.
Bringing Ice Gloves into the Blast Furnace can help when you're using the bar dispenser because they will cool them off quickly for you to collect. This can save you time, instead of lugging buckets of water every time to cool the bars (and it'll reduce inventory space too!).
Before beginning getting to the Blast Furnace itself it's important to know that it's only available in the following worlds: 352 3,55, 358 3, and 387. After you've spoken to the Giant Dwarf and proceeded into Keldagrim You must: Head north and make your way over the bridge. Once you've crossed it, continue south until you find your Blast Furnace icon on the map. In the building that is marked take a walk down and find the furnace.
After you've done this and you're done, it's much easier to visit later on. You can use the Grand Exchange shortcut on the northwest wall, take your time in buy osrs fire cape the minecart that runs through Ice Mountain Dwarven Mines, or utilize the minigame group finder that will let you enter the building.