A guy at a parts counter in Dayton told me to save every old alternator core, and I finally get why
Was picking up a reman alt for a 2011 Civic last Tuesday and the counter guy, Marcus, told me to keep the old core instead of handing it over, because he keeps a shelf of cores for testing. He said 3 out of 10 remans come back bad right out of the box, and having a known good core lets him check the new one on the bench before it goes in a car. I started doing it at my place and sure enough, the next reman I grabbed was dead on arrival. Anybody else keep core stock around for bench testing, or do you just eat the comeback?