Originally Posted by wstar

I still have mine sitting in an oil pan right now too (a well-used one though), mostly because I've been lazy about bottling it and getting it to a recycle place. I don't think oil that's been sitting in a pan for a while can be trusted for analysis though, it's had time for things to "settle out" before you scoop the sample, and it's been oxidizing and absorbing moisture from the air while it sits there too. Hence the oil analysis places always saying to seal up a sample of well-mixed hot oil immediately on drain.