How to Maintain Caulking Gun?

When we use in caulking gun for a long time, sometimes there will occur abnormal situation, How should we analyze and timely repair?
If the caulking gun appears gun leakage phenomenon, we can remove screw, then reinstall the screw, we can deal leakage with glass glue.
If the caulking gun has leak phenomenon on the front part of gun-barrel, the reason why is that the front cover is not close, so we can check the front cover whether are tightened.
If caulking gun appear leakage phenomenon behind part of gun-barrel, it may be due to a broken seal causes, timely recommendations to replace the seals.