Try a Neti Pot. You can probably get a plastic one with pre-packaged sterile saline at your local drug store-- or a ceramic one on line. Basically, it is a small "teapot" that you use to irrigate your sinuses. It helps clear excess mucus while moisturizing nasal passages, which in turn will allow your sinuses to heal. It is very easy to use, if awkward at first. Good luck

Did the doctors ever bother to culture it?

You need to find out what it is before you do something that could spread it elsewhere.

If it is MRSA, Dakin's Solution might help, but that is a mixture of chlorine with a buffer. Strong stuff. You would have to consult a wound control person, there are such specialists, re. how to apply safely. There are also infection control people, but they generally require a referral.

100% chlorine is needed to kill some MRSA's, but it can be very destructive to other tissue and you definitely couldn't use that in a Neti pot.

It needs to irrigated with something strong; "irrigation" could be the key word in seeking a specialist that could help.

Try an ENT specialist (ear, nose, and throat), who could work directly with an infection control and wound control person.

Sometimes ENT peolple will "pack" the sinuses with things, too.

You really need to work with an ENT. When you work with the right specialist, all kinds of new possibilities present themselves.

Get a second opinion from a doctor who cares about your comfort!!