Try carefully feeding the threaded part of the nozzle onto the 3Doodler pen when it is turned on and heated up. Please use the included mini wrench in order to avoid burns. Even if the tip can’t be threaded on fully, the heat from the pen itself will soften the clogged filament inside of the nozzle. After a minute or so, the filament should be softened enough to screw the nozzle fully onto the pen. If you still need assistance, please contact our customer service team at [email protected] and we will be more than happy to assist you.