Through smelting them in the RS gold furnace, you will get molten glass that can be used in the process of making glass. With a glassblowing pipe and a glassblowing pipe, you'll be able to make Unpowered Orbs. To make this process simpler, complete the Hand in the Sand quest. It'll make NPC Bert give you daily 84 buckets full of sand. day.
Another method to level in this phase can be achieved by purchasing gold ore by Blast Furnace and smelting them into bars necessary to craft Gold Bracelets. These will provide you with huge amounts of Crafting expertise and can be later dissolved with High Alchemy for a small profits and more Magic experience.
If you are the Ultimate Ironman, your options aren't much more. The best bet in this scenario is to visit Port Phasmatys and bulk buy soda and buckets of sand. Then, head to the furnace located near the port and smelt them into molten glass to create glass objects. Always strive for the top grade item. It is possible to increase your skill level to maximize the number of experiences you gain. After you have created your items, offer buy Runescape gold them for sale to the general store and switch to another world to replenish the store you purchased them from.