You get a loaf of cheap white bread-- the kind that goes all to nothing, the kind that little boys make bread balls out of and throw around the school lunch-room.
Take several pieces, pull the crusts off, squish the bread into a useful shape, and rub it gently over the painting. Dust and smoke, (My parents smoked for years, and even when they stopped, the painting hung over the fireplace,) and years of neglect will come away. You will notice details you never saw before. If you are lucky, this will be an improvement.
I would post a picture, but right now my phone and my computer are not working together for some reason. (And that is where my photos are.
The other thing that happened was that I tried all day to contact my daughters doctor. I needed a scrip refilled. I was very frustrated that my calls were not being returned. (Very unlike the doctor who is usually so easy to reach.) Finally, tonight I reached the oncall neuro. He said that the doctor herself is in the ER-- he did not, of course, tell me what is wrong with her, but said that she "is much better now, than this morning."
I was so busy getting frustrated with my sensation of neglect, that I had not even thought of that sort of thing. I feel sheepish.