Clear discharge is normal and better than green or dis coloured discharge, however its the quanity of clear discharge that can indicate a problem.
Small amounts of discharge can be normal and no action needed to be taken but in some situations it can indicate dietry problems, oral problems (in the mouth) or blocked tear ducts that may well need flushing.
I would visit your local vet so he / she can check his mouth for any infection, abcesses, and also check the eyes.
If this discharge is a small amount then wiping it from the corner of the eye outwards with damp cotton wool would make him more comfortable.
Hope this helps