No, I don't, but I certainly would. If the stuff is still good (foods that are *highly* perishable such as yogurt, milk, stuff that goes bad fast.. no, not unless it was still cold) and safely packaged so as to not be contaminated, no problem with it. If it was unpackaged foods such as veggies, fruits, etc.. it really depends. Something with a sort of shell or thick layer I can peel off (banana, onion, cabbage, etc), yes. If it's just too easily contaminated, then no. If it was for Middie same rules apply. If it's a freakin day or even with some tings a week or two after its expiration date, I'd still go for it to see if it's good.
Also, if the stuff was thrown into a truly disgusting sort of dumpster I wouldn't touch the stuff on principle, regardless of whether it has touched the disgustingness or not.
With non edibles... UM YES!!!!!!!!! If I were to see something of value sitting in a trash can, I'd take it. Otherwise it's going to a dump.. much better to come live with me!
Another thing... regardless of the cleanliness, due to the way said foods were obtained, I would NOT serve it to anyone else. I know many people simply find the idea of getting food from a trash can repulsive, and in their situation I wouldn't want to be served it without knowledge of where it came from. If it is something that can be contaminated that goes IN or ON your body anyone coming into contact with it has a right to know.
ETA: Wanted to add.... my dad HAS done this before. His company is terribly wasteful, throwing out untold numbers of things because they aren't needed. Paper (of ALL sizes and type.. eve the high quality expensive stuff that costs an arm and a leg for... just this weekend I was in the printing room picking up some stuff for my dad and there was something like 10 feet of blank, perfect paper except for tiny corners that had print that were being thrown away.. I grabbed six feet of the stuff--it's 3 feet wide--for myself and there was still enough to put my art teachers on cloud nine), pens, corkboards, high-quality binders, I can't even begin to tell you of the waste.... so much stuff.. ROOMS full of stuff that they send to the dump each year. We've gotten a lot of good, serviceable things and so have many employees.