wash the junk off the nose..
see if it smells bad..
see if by clearing the nose off, it helps stop the sneezing.
check the nostrils to make sure they are clear.
could be that's all the problem..
the black junk could be dirt.
Vetrx sometimes helps.,..dab a little on end of beak..
Oxine is also helpful
what bedding do you use?
does she have any other symptoms?
lack of appetite, wheezing, swollen eyes..
describe the droppings..color and consistency.
if respiratory illness or infected sinuses is suspected..
Tylan 50 injectable and syringes..available at most farm/feed stores in the LIVESTOCK section.
Erythromycin (Gallimycin) is another good option.
for meds, Oxine..
http://www.firststatevetsupply.com/store/