Non scientific option: Keep your fingers away from the Hi-Z bit at the end and it'll probably be fine ![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
Edit: ordered - new toy to play with at least this month ![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
![](https://imgur.com/0fMSu4P.jpg)
Wow, you went for the glass tube, why? I have my original one still, and I've had it now over 4 years, and it's not actual glass but some form of high temperature plastic
![Evil >:D](https://www.eevblog.com/forum/Smileys/default/evil.gif)
You're right, it is about how you use it, to keep it from clogging up, the trick is to when you suck the solder up, keep the pump running while you withdraw the gun from the thing being unsoldered. This then allows the suction to suck the solder all the way out of the nozzle and impact the filter in the "glass" tube, so you are ready for the next job, next time. Just don't suck up too much solder at each session so that the tube gets more than about 10 to 15 mm of solder otherwise you will struggle to separate the spring from the solder.
![ThumbsUp :-+](https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif)