I guess I’m lucky that every auto parts store near me takes used oil for free. I drain my old oil into the “pan,” set it aside and do the oil change, and then i pour the pan of used oil into the now-empty jug that had my fresh oil. I take a sharpie and write OLD on the jug. I set that aside in the shed. Then when it’s time for my next oil change, I grab that jug of old oil out of the shed and take it to the auto parts store where I dump it and then buy fresh oil and a filter – one-stop shopping. Easy peasy.