Hi there and thanks for your question.
Most likely this is nothing to worry about. However, if the discharge is green or yellow in colour this may be an infection. You can certainly keep wiping the eyes as necessary. If it is an infection it will probably get worse. There really isn't an over the counter medication so you will need to see the vet to get some antibiotics.
However, it could possibly be due to allergies. Most dogs with allergies will have skin manifestations instead, but it is still possible. You may want to consider trying benadryl. There is information about that here:
One final possibility is that your dog has a condition called "dry eye" in which the tear production is altered. Dogs with dry eye have a really gunky yellow discharge. Your vet can diagnose dry eye with a simple inexpensive test. Some dogs with dry eye do really well with over the counter artificial tears given 1-3 x per day but some need prescription medicine.
I hope this information helps! If you have more questions regarding this problem, just hit reply. If I am online I will respond right away. Otherwise I will respond as soon as I come online again. Or, if my answer is sufficient, then please hit accept. Thanks!