Filter screen must be installed before the cooling water inlet of induction smelting furnace. If it's blocked, it's really hard to do. Besides, I don't know where to block it, but I can probably find the blocked position. The inner diameter of the coil is large, so iron wire can be used to go inside. First connect both ends, find the shortest distance, and see if we can hook out the impurities inside. If it's blocked by oxide, dilute sulfuric acid can be used. If it's blocked by oxide, dilute sulfuric acid can be used It's other things that don't melt and can't hook out. The only way is to take apart the insulation board, burn it with fire, heat it to a certain temperature (it's ok if it doesn't burn red), and burn off the sundries inside. If you know the approximate position, you can also use oxygen to heat it locally. When heating, try not to deform the coil too much, otherwise it will be a bit troublesome to install it back. I burned it once and it worked fine. It has no effect on later use.