Oscillating Bonfires are very useful things, and a great thing to learn about. They will enable you to produce things such as Ash, Charcoal, Grilled Fish and Lime. While there are "easier" methods of producing these items, they involve wasting a great deal of Wood and other resources. The oscillating method allows you to achieve a 100% efficiency rate, although it does require some work and constant monitoring.
You will need the "Controlled Burn skill", available from the University of Body for free. This will enable you to build Bonfires from your "Projects" menu using Wood.
To set up a timer, click on the "Main" chat window. Now go and find a tree. Click on the tree to harvest some wood, and immediately type "00" and press Enter. "Pin" the tree menu, and keep clicking it to refresh the amount of time remaining until you can gather more wood. As soon as the time remaining on the tree has dropped by 10 seconds, type "10" and press Enter. When the time remaining on the tree has dropped by another 10 seconds, type "20" and press Enter. Repeat this another three times at 10 second intervals, but type 30, 40 and 50. Once done, type "/ts" to enable time-stamps. You should now have the following in the Main chat window:
01m Yourname: 00
00m Yourname: 10
00m Yourname: 20
00m Yourname: 30
00m Yourname: 40
00m Yourname: 50
You now have a timer measuring one TeppyMinute. The first message is already at "01m" as a minute has passed since it was posted. When "Yourname: 10" changes to "01m", 10 TeppySeconds have passed, when "Yourname: 20" changes to "01m", another 10 TeppySeconds have passed, and so on.
| Resource | Product | Temperature | Burn Rate | Product Rate | Comments |
| Cabbage | Ash | 20-30 | 13 per Tick | 1.8 per Tick | x |
| Carrots | Ash | 15-24 | 8 per Tick | 1.5 per Tick | x |
| Fish | Grilled Fish | 10-20 | 1 per Tick | 1 per Tick | x |
| Garlic | Ash | 9-11 | 4 per Tick | 1.2 per Tick | Best for Ash when using Oscillating Bonfire. |
| Limestone | Lime | 7-9 | 1 per Tick | 0.7 per Tick | x |
| Papyrus | Ash | 5-10 | 1 per Tick | 0.4 per Tick | x |
| Wood | Charcoal | 4-8 | 1 per Tick | 0.5 per Tick | 0.5 Charcoal per tick destroyed at 13+ heat. |
Note: "Products" are only made when a Bonfire is at the correct temperature. Above or below this temperature resources will still burn, but no products will be made. Also of note is that resources will start to burn as soon as they are added to the fire (assuming the fire is lit). For this reason, it is best to stoke the fire to the correct temperature before adding the resource.
Finally, you will need to work out how long you need the Bonfire to be burning at the required temperature to burn all the resources you are intending to use. For example, if you want to make Ash using 200 Garlic you will need the fire to burn at 9-11 heat for 50 Ticks (500 seconds - 8 minutes 20 seconds). This is because Garlic burns at 4 per Tick.
Be sure you have enough wood to keep your Bonfire going. There is a simple way to figure out how much you will need. Take the number of Ticks required for all of your resource to burn, divide that number by two, and then add the heat required. The resulting number is the amount of Wood you will need. For the above Garlic example, it would be 50 / 2 + 10 = 35. As most resources have a burning range, aim for a temperature in the middle of that range. This allows for small errors later on which may cause the temperature to fluctuate slightly. So for Garlic, which burns at 9-11 heat, you would aim for a temperature of 10.
Total Ticks / 2 + Heat = Wood required
First build the Bonfire using 2 Wood. Click it, and "pin" it's menu. Now watch your timer. As soon as "XXm Yourname: 00" increases to show a new minute, click the "Light this Bonfire" button. Immediately click the Bonfire's menu (anywhere other than a button) to update it. It should now show the fire as burning, containing 1 Wood. There should be two buttons available, one to add more wood and one to add your chosen resource. Keep clicking the menu repeatedly to update it. After around 10 seconds the menu will show that the fire contains 0 Wood. As 2 Wood have been burnt, the fire is now at a heat of 2. Click the "Add Wood" button and add 1 Wood. Keep clicking in the menu again. After another 10 seconds, the menu will show 0 Wood again. The fire is now at a heat of 3. Add another 1 Wood, and at 0 Wood the fire is at a heat of 4. Repeat this process until you have added enough wood to get the fire to the correct temperature. Note the Tick in which you made the last Wood addition on your timer. On the next Tick, add your resources but no Wood. They will now start to burn.
Now you have to keep the Bonfire's temperature constant until all resources are burnt. On the next Tick (2 Ticks after the last Wood addition - 20 TeppySeconds), add 1 Wood. Watch your timer. On the next Tick (10 TeppySeconds), do nothing. On the Tick after that (20 TeppySeconds), add another 1 Wood. On the next Tick, do nothing. On the one after that, add 1 Wood. As you can see, you are adding 1 Wood every 20 TeppySeconds. This is how you keep the temperature in the right range. On the Tick that you do not add Wood, the Bonfire will drop 1 heat... when you add 1 Wood on the next Tick, it will gain 1 heat... and so on. Keep adding Wood every 20 TeppySeconds until you have used all the Wood you started with.
Now you simply let the fire burn itself out. Do not try and rush this process by adding water, as it can lower your total yield. Simple leave the Bonfire for a few minutes and it will go out on its own. When it does, the products made by the resources you burnt will appear on the ground. Even if you were not specifically making it, you may end up with some Charcoal too.
And thats all there is to it. It may sound a bit long-winded and complicated when written up as a guide, but once you get the hang of it, its actually quite easy. However, it can be a long process and will require your full attention... so it can get rather boring. However, once you are used to the process, you could easily run more than one Bonfire at a time. Some people have been known to run 10 or more with little difficulty. A final thing that is worth noting is that you are not restricted to adding only one resource. If you are using a temperature at which more than one resource can be burnt, simply add both resources once you have stoked the fire to that temperature. A good example would be Garlic and Fish, with a fire of 10 heat. Also, if you want to be really clever, you could use the same fire for resources that do not burn at the same temperature. Simply burn the resource that requires the highest heat first, let the fire cool for a few Ticks until it reaches the heat requirement of the next resource, add the resource and start the oscillating process again. Simple. However, I leave those advanced details for you to work out on your own...