this is actually called "GOOP" it how slot car guy restore valuable bodies.
however better then acetone is Testors 3502 glue solvent.
you would need a lot of it but it works better then acetone.
same idea you dissolve the original plastic from a donor part with the same color if possible and use it to repair the original.
you can also perform a color change, you dissolve the plastic in the pigment of your choice and using an air brush you paint the original part with the new plastic pigment. it sticks better then paint and you get a total color change to the surface in the original material. we use dyes and paints for this now.
google how to make goop testors various hobby sites will come up...
it can be used to repair de-laminating plastics.
there are also Acetone baths you can google with can smooth out plastic that is falling apart at the surface.
basically it is like 3d printing.... in the future you will be able to 3d print new interior parts.
i restore old toys and collectibles so i have been doing this for years
good for custom builds also.
example of custom suspension arm made from goop and hand shaped.
[THUMBS UP SIGN] Thank you very much for sharing this whit us All [THUMBS UP SIGN] Regards Lars 
