Hi, today I was cleaning a couple of well-used roarer burners, using my ultrasonic cleaner and decided to take a few photos and make this post. The ultrasonic (U/S) unit which I have is relatively low power, max. 50W at 240V, and is intended for light household use, such a cleaning spectacles, jewellery and watch straps. These units are relatively cheap and I find it adequate for smaller stove parts and burners. The cleaning solution I use for stove parts consists of a teaspoon of citric acid crystals and a few drops of detergent in hot water. Brass parts, such as are used in classic stoves, should not be left in this solution for more than a few minutes as zinc can be preferentially removed from the surface layers of the metal, leaving a red, copper-rich deposit which has to be removed later. Always remember that you are trying to remove surface oxide from your item, not metal. You don't need to use the whole bath to hold the solution. Put an open glass jar, or cut-down polypropylene bottle, with the burner and solution into the water-filled ultrasonic tank. The ultrasonic waves pass directly through the glass or plastic without losing significant energy. In this way you keep the main tank clean, and use less cleaning solution. Remember though that the tank must always contain water when operating, to act as an ultrasonic coupling agent and prevent the ultrasonic transducer from overheating and destructing. My U/S unit has only two controls; an “on” button which initiates a fixed cycle of around 3 minutes, and an “off” button which allows you to stop the cycle at any point. For most domestic items, a single cycle is often enough. For burner heads I take the item out after each cycle to check progress and shift loosened dirt with an old toothbrush, or similar. I seldom exceed two cycles in the citric acid solution. Remember, if your burner starts to turn red, STOP. You can give your cleaned burner a final U/S cycle in a water and detergent solution or just rinse it under a tap, to remove any acid residues and dirt. You can now dry your cleaned burner with your partner’s favourite hair dryer. Here are a few photos: This is the colour of the cleaning solution after 2 cycles (6 minutes) of operation. Best Regards, Kerophile.