I don't think you can other than steroids.  Soem people weill suggesst Xylitol
etc. but it is not too clear that it will help much.

If you eliminate inflammation in nearby areas then that should help.

I don't know if our problems are the same or not.  I didn't even know
that I had problems with my frontal sinuses, as they are very small.  I
thought it was all due to my ethmoids because most of my pain/pressure
has been behind my nose and eyes, with extreme pressure on top and
behind my head sometimes like a band (the sphenoids?).  There was bony
thickening in the ethmoids that was suggestive of osteitis, but Dr.
Sherris doesn't think that is a problem.   I have had a couple of CT
scans that have shown a small amount of fluid in the left frontal which
is the one that I think he said was the worst.  I don't know exactly
what he did to open them up, along with the sphenoids, but I know that
is all that he did, no removal of tissue, stents,  etc.   He did do a
biopsy and cultures, and there is still some question of allergic
fungal sinusitis.   But since I have had to be on prednisone to get my
sinuses to drain at all, it might mask the results.   I am supposed to
be getting the final report next week, because they are on vacation
this week.

I've been doing a little research on frontal sinusitis and it appears
that everyone is anatomically different in the way the frontal sinuses
drain, and since some of them drain into the ethmoids , then maybe that
is why my pain has been there.  You are right, there are ducts, but
also ostia, the opening into the ducts.

There is a good article about frontal sinusitis at:

  http://www.bcm.edu/oto/grand/110291.html

Here is a small excerpt:

"Fifty-five percent of frontal sinuses drain directly into the frontal
recess, 30% above the ethmoid infundibulum, 15% into the infundibulum,
and 1% above the ethmoid bulla. The frontal sinus, not present at
birth, develops from either the frontal recess or from anterior
ethmoidal cells. It is radiographically visible by seven years of age
and reaches full size by adulthood.
The etiology of frontal sinusitis stems from blockage of the
nasofrontal duct ostium. Mechanical obstruction and local mucosal edema
lead to symptoms of frontal headache, fever, rhinorrhea and cough."

I didn't have any complications from the surgery;  it was mild compared
to the pain that I was having.  It is probably too early to tell if
this is going to work.  I still have pain/pressure, but not quite as
bad.  There seems to be a more constant drainage most of the time now
instead of the buildup for several days, and then it all coming out at
once making me about strangle on it, so I'm trying to have hope that
this is going to work.  There is still some kind of
infection/inflammation? because I still have the nasty tasting drainage
(that was present before surgery).  It is gritty, like sand.

I would not consider surgery to be a last resort if you are talking
years instead of weeks and/or a few more months.  On the other hand, if
you can hold off a little longer and continue what you are doing, then
maybe you won't have to have surgery.  I did not know anything about
saline irrigation when my problems first started.  I have also found
xylitol to be somewhat useful in dissolving the mucus.

The real problem seems to be finding an ENT to take your symptoms
seriously, especially if not much shows up on the CT scans.  If you
have read my other posts, it has taken me years to get someone to do
so.

BTW,  have you been diagnosed with the frontal duct stenosis?   I would
guess that if that is the case, then you will most likely need surgery.