Reading through the latest oil thread in Outboard Non-repair (which turned out to be interesting for a change), I came across where someone mentioned that changing oil often only contributes to the using up of oil supplies. Which made sense to me at first, but then I thought about the fact that I drop off my oil after changes at the county recycling center. <br /><br />I'm totally ignorant about what happens after that, and I figured somebody here knows. Do they just sell it to refineries to do something with it? What do they do to it? Clean it and put more addtives in it or what? How usable is old oil? As always, thanks for the enlightenment!