Trying out some chemicals, side-by-side to see results.
synthetic chair, off-white, with body oil on the arm rests.
There are three chemicals
1) Upholstery foam made by local Jan company.
2) Realsit DS
3) Realist Hydrox
The process is as fair as I know how...two chairs, four arm rests equally soiled. Of course they can both be wet-cleaned but my choice is not to for case of science

there are also four arm 'covers' used (n theory) to protect the arm portion of the chair(s). These are quite dirty as well.
I have cleaned three of the four arms and the side, tops and backs as well.
They are in the drying process right now but the results are very impressive.
I will report MY findings once all if dry.