Good to go on the neti pot. Will have to try the vinegar.
Cayenne pepper is recommended for sinus too. Its on the web for that too.
I gargled some stirred in cayenne pepper and warm water for sore throat about 2-3 times a day - stopped it really quick. Was quite amazed, like bam.
Although, I had to plug my nose and barely open my mouth or the cayenne pepper gets airborne. Its a tricky sip - wouldn't recommend it for children.