Thanks Dave. I went back and read this thread from the start and found the +ve results reported by most to be really encouraging. The eustachian tube manouver sounds complicated but I'll likely give it a shot. I'm just not sure of the mechanics yet of getting the tubes to open -- but then I'm not even sure if there's something closing them off.
It's really quite simple, so it must just need a better description than I gave.... Look out, here it comes!
The mechanics, as I understand them, as a non-expert, are that nasal passages, nasal sinuses and other structures, such as eustachian tubes, will vary from one person to the next in terms of how easily they will open and drain or get clogged and trap debris and/or infection.
I feel lucky that I'm not prone to getting the severe recurrent sinus infections that some have reported, but I've had milder sinus infections that occasionally drag on for months. So, thankfully, UnderSeaBumbleBee's thread got me to try the saline irrigation route. (I'm indebted, USBB!)
However, when I tried to irrigate using gravity alone, I was quite sure my sinuses weren't getting irrigated at all. I did some experimenting and found that forcing the saline solution into the passages was the only way I would effectively clean out those semi-closed passages. I'll spare you the description of the visible evidence....
A secondary benefit, I concluded, was that the process of pressurized irrigation exercised my eustachian tubes and I subsequently found it easier to clear when diving. Others have reported the same effect by practicing clearing just by using the technique of pinched nose/Valsalva maneuver with air alone.
The mechanics of getting the eustachian tubes to open is simple either way. You're simply pressurizing them and then they depressurize, usually passively or sometimes with some jaw movements or swallowing or slight re-pressurizing, etc.
As far as irrigating the eustachian tubes when I do my thing, I'm not even sure that's occuring or even advantageous, but the exercising of the tubes is definitely a good thing. I haven't seen any problems using saline to do it.
If you were asking about the mechanics of using a syringe to pressurize the nasal saline irrigation, that's simple, too.
With my head tipped back, when the saline-filled 60cc syringe hub is inserted into a nostril, I press the base of the syringe against the nostril to seal it. Then I inject saline until the open passages are filled with saline, that is, when the saline starts to run out of the other nostril. Since my head is tilted back, there is no longer any air in those open passages, just saline.
As the next loads of saline are injected, I intermittently pinch the other nostril shut while saline is overflowing, thereby pressurizing my nasal passages and forcing saline into the semi-closed areas, such as sinuses and, possibly, eustachian tubes, which makes my ears pop. The air in those semi-closed areas is gradually replaced to some extent by saline. After injecting/irrigating 8-ounces of saline solution, I can actually hear it sloshing around when I shake my head. The saline continues to bathe those semi-closed passages while I finish my shower.
The process of clearing the saline from those passages is a simple matter of tilting the head forward, and alternatingly pinching and unpinching both nostrils timed with intermittent blowing to create and then release pressure in the nasal passages. This time, because of the position of the head, the saline in those semi-closed passages is near the openings and will be ejected and replaced with air. It might take me ten such pressurization cycles to get most of the saline out, sometimes aided by changing head position side to side.
So, I'm probably guilty of providing WAY Too Much Information, but there it is.... You asked for it, more or less!
I hope it answers your question about the "mechanics of getting the tubes to open".
Dave C