Get a funnel, a coffee filter or cheesecloth, and a clean milk or other sealable carton. Once the used peanut oil is cool you can then filter it through the coffee filter/cheesecloth, store, and use it for cooking other things. Oil, unless you burned it badly (got it above its smoke point and kept it there for a long period), can be reused. You wouldn't want to use it as oil in recipe sure, but you can cook in it again, multiple times even. After all, it's not like bacteria or viruses will survive the temperatures you get oil to when cooking and so long as you've strained it for large particles, you're generally not going to be carrying over any flavors beyond what's already in the oil.
NOTE: this mostly applies to oil used for deep frying. You can, theoretically, do this for oil used in pan frying, but generally speaking the particulate to reusable oil ratio for that is way lower so its questionable if it's useful there, depends on the cost of the oil. Obviously you're not going to recover the oil used when sauteing.
Oh, and if you use a GLASS container and a metal funnel for this process you can do it with hot oil and then let it cool. This is useful for cooking oils that are not liquid at room temperature like lard, tallow, and the ultimate frying medium: bacon fat. Using the hot method you can recover rendered BACON FAT and store it for future use.