Kathy,

My cats Mollie Rose (9) and Lil Eli (1) do the same thing. Mollie Rose was diagnosed with kitty asthma and takes Prednisone once in a while when the asthma attacks get really bad. She also sneezes alot and has green junk coming out her nose. The vet took a culture of it and said it was nothing to worry about. She has now been labled the "booger queen".

Lil Eli gets them once in a while but it's not as bad as Mollie's. As long as they're eating, drinking and using the box and the vet isn't too concerned, I wouldn't worry about it. I'm sure if the vet was concerned he would've done tests.