Neptune's Harvest Fertilizer

Two or three years ago, I bought a gallon of Neptune's Harvest Fish and Seaweed fertilizer concentrate at a fantastic savings because it had been sitting outside in the sun and rain all summer in a display at a local garden center and it didn't look like any upscale type gardener would want to put in their clean SUV. It is a great product. To make a long story longer, after three years, I still have about a third of it left and it stinks to high heaven. I have tried to call the company to see if it still effective as a fertilizer,but can't get any one to answer the phone...... no e-mail consumer help line either ....so I am just wondering if the stuff is still good or whether or not I should call our volunteer fire department, hazardous waste team to dispose of it. They do have all these fancy new Hazmat suits from the stimulus money. If the Neptune's Harvest could still stimulate my veggies, I could use it before the afternoon on shore breeze comes up but if it has lost its fertilizing ability would use the new gallon I bought instead. Any have any experience with old Neptune's Harvest?