when I find brass the first thing I look for is a box that it came from, that'll tell whether it's new or not... if no box you can inspect the brass for stretching or ringing etc... I use the brass, or pass it on to a bud of mine who uses it for either his own or people he loads for, so yes I do use range brass...
salvage yards will pay good money for brass... they will buy up military surplus if they can get it for the right price for recycling...