How do I deal with a stuffy nose?

For whatever reason, I keep getting a stuffy nose. This forces me to breathe with my mouth and I look dumb doing so.

Things I’ve tried so far that did not work include:
*Cleaning my surroundings
*Taking Claritin and similar
*Taking Benedryl
*Tongue on roof of mouth trick (does not always work)
*Blowing my nose

This happens sometimes when I am in public too, so any remedy that would involve boiling or cooking something would probably not work for me.