If you're looking for the fastest way to level up your Invention skill in RuneScape, then look no further than Smithing burial Armor sets. This method involves smithing Elder Rune armor sets on the forges in the back of the Artisans Workshop and is one of the best ways to gain experience in the game. The only downside is that you will be losing Elder Rune armor sets in order to gain the high experience rates. 

To get started with this method, you'll need to have at least 99 Smithing, 99 Firemaking, 22 Invention, and the Superheat Form prayer unlocked from the Within quest. You'll also want to bring with you a Power Burst of Master Stroke, an XP Capacitor, a Smithing Skill Kit, a Hammertron or Crystal Hammer with Tinker 4 and Rapid 4 perks, a Perfect Juju Smithing Potion, and a Super 8 Form potion. 

There are two methods for this training method, the AFK and the Superheat Item Spam. 

For the AFK method, you'll need to make a bunch of unfinished Elder Rune sets and start smithing them. Make sure to sip your Perfect Juju Smithing Potion and use a Power Burst of Master Stroke whenever it's off cooldown. You can also use an Advanced Smithing Auto Heater to get your items back up to maximum heat. 

For the Superheat Item Spam method, you'll need to be on the Normal spellbook and have a good chunk of Nature and Fire runes in your inventory. You'll keep buying the Superheat Item spell and mash the key bind while clicking on the unfinished Elder Rune sets in your inventory. This will increase the speed at which you finish the items and give you around 20-25% more experience per hour. 

In terms of experience rates, you can get around 2.3 million Smithing experience per hour with the AFK method and almost 2.9 million with the Superheat Item Spam method. You can also get 192-239,000 item experience per hour with the Hammertron and up to 6.6-8.2 million Invention experience per hour with the XP Capacitor and Double XP event. 

Overall

Smithing burial armor sets are an incredibly fast and efficient way to level up your Invention skill in RuneScape. With the right setup and a bit of effort, you'll be a master of Invention in no time!