Storm Crow's on the money. Its a pain in the ass to change the screen. Vaping is all about getting the most airflow through your bud with your bud having the most surface area possible. When the screen gets clogged, you're losing efficiency. I used to use one of of those long neck butane lighters to clear out the screen. I also used a bamboo skewer to install the new screen.

Easiest way for me was to remove the tube, put a stick of chapstick into the backend of the bowl and then use a bamboo skewer to work the new screen down the mouth of the bowl and then use another stick of chapstick to push the screen flat and into place.