Have you tried using NeilMed Sinus Rinse? It's a plastic bottle and you squirt water with salt solution added to it up one nostril and it comes out the other - very effective at shifting mucus.
Also steam inhalation over a hot bowl of water with a towel over your head and a few drops of Olbas oil?
Both these could help - they've helped me when I've had sinus issues.
Hugs xx