My dog has recently (a day or two) started getting green gunk by his tearducts, he gets it a few times a day after naps or resting, I'm worried it's more than just sleep in his eyes since this has never happened before, what could it be?

What type of dog is it?
How old is he?
Try looking in your dogs eye could there be a hair or dirt in its eye?
Wipe with warm water and an soft cloth,some say saline water to clean it if its conjunctivitis.
Is the whites of his eye red? Swollen,is he squinting,trying to rub his eye on cushions,bed,paws.
Does his eye lashes look like there turning in?

What type of dog is it??
How old is he?
Try looking in your dogs eye could
there be a hair or dirt in its eye?
Wipe with warm water and an soft cloth,some say saline water to clean it if its conjunctivitis.
is the whites of his eye red?
swollen,is he squinting,trying to rub his eye on cushions,bed,paws.
Does his eye lashes look like there turning in?

He's a Jack Russell, just over 3 years old, I've been wiping his eyes with warm water he's starting to get it now without resting or sleeping, his eyes are still dark no redness and he's not at his eyes anymore than usual his eyelashes seem fine also, he's still a young dog so I doubt it's catarachts any ideas?

A quick trip to the vet to make sure he doesn't have any scratches on his cornea would be a good idea, or it could be conjunctivitis, but it sounds as if there is certainly some sort of irritation.
Until then use only a saline rinse to clean them the rinse will not be contaminated as a cloth may be.
You can pick up saline flush at any store or pharmacy.
Don't use any ointments or drops in them if there is a scratch the wrong medication could harm the eye. Better to let the vet have a look and prescribe something.