Both my girls had or have Upper Respiratory Infections, and I only knew because of the gunk under their eyes and in the tear ducts...
I was given amoxicillan and triple antibotic cream to put in their eyes.
As for the stains,, Angel is a white cat, and her fur did stain a bit,, but using a warm wash cloth every single day, at least 3 to 4 times a day to clean the eye area,, it eventually wore off!!
Don't worry it'll go away.. My vet said not to use any thing but warm water and let it sit on her eye as so it'll come right off. She said I could use a cotton ball or qtip and that was it!! She said that it's common that if you use an eye wash you can hurt their eyes or scar them!!!
Have your babies eyes check out.. If you don't,, you could hurt their eyes for life..