OK -- I maybe anal, but about 2 years ago, I decided to drip dry all my new oil qts. into a new empty qt. Basically, I let the quarts drip a few moments into the filler plug. Then, I let them dip overnight into a clean, empty quart. I just did this for "kicks" -- to see how much would accumulate over time. I now have a 1/2 QT! The problem is, this is a mixture of different oils and weights (mostly 5w20, and some 5w30). If it were all the same oil/weight, I could use it in my new car which takes 4.5 qts. What should I do with this new, virgin mixture of oil? Should I use it in an oiling can? Could I still use it as that 1/2 quart in my new car? It's too thin to use in the 10-yr old lawn mower. Your thoughts are appreciated.