Stuffy nose or congestion? The best tool I've found to clear my sinuses is the neti pot, which seems a bit intimidating at first but it is so simple and does a great job at flushing out mucus.
I prefer using the neti pot over over-the-counter decongestants because of the unpredictable chemicals and side effects that can come with medication. It's great to use the neti pot every few days just to rinse out debris and allergens from the nasal cavity - I’ve been using mine for years! Below is a quick tutorial video on how to use it.