All of that said and not withstanding, sometimes it is done as part of a restoration. In the case of the doll head here, what we had was not original varnish but a dark smeary mess put on I guess to even out or conceal considerable wear and a bit of damage. Someone before me had rubbed off part of it on the face. I bought this large Greiner head because of its size, condition never mind. The size 12's are not readily found. I have had a few size 13's. So here is the doll and here is how I cleaned the varnish. Be aware that more finish may come off than you want, in this case I lost a few eyelashes on one eye.
Some people would have left this stuff on her and will feel I have over cleaned her. That is absolutely a risk every time. This is a value judgment, everyone has to work this out for themselves.
I gathered 70% alcohol from my bathroom, cotton balls and cotton swabs. Jack would have used denatured alcohol. I tested the procedure on the right side of this picture low on the doll's shoulder plate. See where it has lightened. Often a modern varnish will not come off with alcohol and I have to leave it. Alcohol is flammable so the cotton mess is now out in my yard to dry for a couple of days. We had one spontaneous combustion fire in a work shop and I never want another. I treat even a small amount of soiled material with respect.
She will get a few dots of gesso in the dents, and careful in painting with ceramcoat acrylic paint in Dresden flesh color. I will not touch her eyes or nostrils or mouth nor run all over her touching every little mark on her, but rather confine the tip of my brush to the damaged places only. As expected she has lost a bit of character from loss of accumulated soil in the indented places of her face, corners of her eyes and so on. I miss that and also miss the slight sheen that would have been there on her original finish. Lets hope she forgives me. Again please do not do anything to a doll head with its original finish. This one had been coated over and roughly in painted, but thankfully not on her features.
Her sisters will welcome her when she has a new body and clothing. She is a bit the largest, but not quite as much as the camera makes us think here.
Above is another Greiner doll, with her original finish, showing a little dirt and a bit of wear and a nose ding, and I would not think of touching her. e