I eat a lot of take out food from restaurants in my neighborhood area and I get a lot of take out containers after eating those foods. I usually throw them away because I find it very difficult to wash them, especially when the take out food were oily and greasy.
I have tried washing a few of those take out containers, as I find them quite sturdy and of good quality. It is such a waste to throw away such good quality take out containers, when I could at least use them several more times.
That is if I could clean and wash them properly without the need to wash them several times with dish soap and water. You know, how tedious it gets when I have to wash each take out containers for several times with soap and water, only to find that they are still oily and greasy.
I don't know what material those take out containers are actually made of, but they tend to attract and retain a lot of oil and grease from the food, and makes it revolting to the touch. (I don't like the touch and feeling of grease and oil in my hands at any time).