Even if you think it merely mucus (clear, thick, etc as Krista said) and decide not to go to your vet, this is now a time to begin thinking holistically, realizing that there are a lot of very minor symptoms that can indicate an internal imbalance – see more at http://christinachambreau.com/learn-more/free-articles/early-warning-signs/early-warning-signs-of-ill-health. Feeding fresh food, not vaccinating except for rabies, avoiding chemicals (in food, fleas, yard, house, etc) and learning Reiki or other healing methods will help you deal with discharges of pus or mucus.