I was trying to recall something I have read previously concerning oil evaluations. I am about to run synthetic oil and would like to be able to do simple and cost effective oil evaluations along the way to baseline the oil breakdown. I may be crazy, but I have heard that you can put a drop of oil on a paper towel and if the outside ring left by the drop is some odd color or another, that means that the oil is beginning to break down.
Are there any oil evaluation techniques that are relatively simply and cost effective, out there that anyone knows about?
Thanks in advance for any and all assistance!