If you unscrew the brass tip, the finned cylinder on the other side of the block should come free. Then you can check where the blockage is. If it is in the brass tip, you could put the tip in an oven set to the oven's hottest temperature. This will melt the filament and you should be able to feed a length of fine wire through the hole in the tip.

CAUTION!!!! Wear a heat-proof glove when you take the tip out of the oven, or use metal kitchen tongs to hold it.

Old Man Emu