I've been trying that and it doesn't help. I even looked at the dipstick using one of my loupes and still none the wiser. I think I'll borrow a dipstick with crosshatching and stuff it part way in the dipstick hole and see if the fluid shows up on that. If it does, I will most likely add crosshatching with one of the very small files that I have.
If you can't see where the paper towel changes to "wet" there might not be enough light...or, -heaven forbid- you're becoming ancient.
So far I've gotten by drying off the stick with paper towel and using an "everyday carry" (tiny, but extremely bright) LED flashlight held in my mouth to see where the oil glistens, because when the paper towel trick was "possibly inconclusive" I determined the paper towel was too high of quality (not thin enough) and that was my problem--which might also be your problem, too good of towel (not kidding, the cheap stuff turns almost clear instantly).
That yellow plastic is kind of shiny,
@chim has a good idea with sanding the surface.
Thanks for the well-wishing, I slept in this morning (again) and will likely try an old remedy tonight to cook it out of me. (Had a bad dream I got hired in the office of a super-strict genetic seed company, suit, tie, and rules about everything, can't carry at work, security scanners, cameras everywhere, you know the type.
I lasted 40 minutes...

)