
Firstly does your dog have any eye problems, entropion/distichiasis/
dry eye etc?
If so vet treatment will be needed.
Excessive tearing can be caused by several things and some are non health threatening -more unsightly really.
Young dogs, certain breeds and white faced dogs seem to be plagued with tearing (and I'm not referring to gunky infected discharge).
I buy a product called 'Kleen Face' in the largest size and decant it into a small spray bottle ( 50mls) from Superdrug. It's soothing, calming and can be sprayed around the eye area quite safely.
Using lint-free tissue I clean the area from the outside into the corner and then away up to the forehead - dont rub or apply too much pressure - this makes it sore.
In between times, if the staining or tearing is heavy, I make a paste of witchhazel and fullers earth and use this as a barrier to the skin under the eyes, it soaks up and needs replaced daily. The idea is to let the skin under the eye dry sufficiently for the skin to recover.
DO NOT get this paste in the eye.
Cotton wool fibres in the eyes are very irritating as they are so tiny and get caught in the eyelashes - best avoided, ordinary paper towel is better than nothing.
Lastly - I am never without a product called
Murine, an over the pharmacy counter soothing eyedrop which I've used for all my human and doggy family over the years. 1 drop in tired/bloodshot/gritty eyes and it's bliss. Not to be used if you wear contacts but I use it in the event of any itchy, tired eyes.
Good luck