So I found 4-5 new unopened qts of Chevron 2 stroke hidden on the back of a shelf at work. The bottles are marked 12/99 and have been stored inside a heated and air conditioned room. They're free if I want them. The oil looks uniform and is free from clumps. Any thoughts about using this oil in leaf blowers ( 4-mix and a 2-stroke)? I just finished a 10+ year old bottle of Shell 2-stroke, so old doesn't scare me, but these are really old!