Is it ok to store peanut oil in the container it came in after being used

The boiling point of most cooking oils is much higher than their smoke points. The boiling point of olive oil, for example, is around 300°C (572°F), which is hotter than the temperature of a pan on a typical residential range/cooktop. With that said, alcohols and esters which make up the flavor and fragrance of the oil will have lower boiling points and will therefore evaporate. That should not significantly alter the nutritional content of the oil. Furthermore, much of the perceived loss of oil is likely due to a combination of absorption of the oil into the items being fried, and also due to splatter. The latter cannot be easily quantified due to its connection with the cooking vessel and the technique of the cook.

For the very best tasting fries, onion rings and battered fish are fried in fat made from rendered beef fat. When I was a cook we rendered down a thousand pounds of beef fat a week, it took days to do. But it made the very best tasting savory deep fried foods. The burning temperature is lowish, so food needs to be cooked at 325 and changed more often. It's not good for things like doughnuts.

I'm not a fan of Canola, I find it often has a taste which I don't like. I don't use peanut mostly due to habit, too many people I've run into with allergies. I can't find rendered beef fat and I'm not going to render it at home.

At home I use a mixture of Sunflower and lard, about 1 part to 3 parts. The sunflower oil makes it easier to handle when filtering through a very fine mesh sieve (more liquid at a lower temperature) after use, then I put it in an old olive oil can which I refrigerate between uses. I leave out overnight before I use it then warm in hot water to pour it out. I don't usually use more then once a month. The more crumbs and batter bits you filter out the longer the fat will remain good. So filter, and don't pour the last bit into the can.

Refrigerated the oil mix doesn't go bad before it becomes no good to use. I get well over a years use. I love sunflower oil, it has almost no taste at all and a high smoke temp. It is pricey.