They will smell bad if they have gone rancid. What you can do to extend their life, is to get some ROE. If the ROE is added to the oils before the oxidation occurs it can extend their shelf like by several months. Also storing in the fridge, and transferring them to smaller containers as you use them. The smaller containers help prevent spoilage because less surface area of the oil is exposed to air. If the oils are old but not yet bad, they are okay to go into soap, but I wouldn't use them for body lotions or balms or any other leave-on product.
To dispose of it, you could donate it to someone who makes bio-diesel. Lots of restaraunts have oil recycling bins which are then picked up for bio diesel. If its a small quantity its suggested to dry it with cat litter, sawdust or sand before putting into the garbage. Theres a service called "Fat Trapper" in some areas too that will dispose of cooking oils. The bottles themselves have to be cleaned of all the oil before putting into recycling.
The oils are also biodegradeable, so they can be poured into your yard or compost pile. They are never to be poured down the sink because they will clogg pipes and sewer systems and could cause a backup problem in someone elses house.
Your municipality should have instructions about disposing of cooking oils. Mine says to dry it up with cat litter, sawdust or sand before putting in the trash.
