Rubber baby doll

Hi I'm new to your site, in fact quite new to the computer. I wonder if any
one can help me. I have a small doll about 9", I was given it when I was
born (1949). It is made of what I think is rubber, it was originally pink
but is now light brown. The rubber is inclined to go sticky on the surface
but is still smooth and solid under the stickiness. I wonder if any one can
tell me how to preserve it, I have tried powdering it with chalk, keeping it
in the dark and last but not least wrapping it in clingfilm.On the back of
the doll is the name: -

Marie Josie
pro.pat.30189/45
pro.pat.31718/47

Has any one else got one of this type of doll , I have never seen another.
Another of it's oddities is that it has a lead weight inside the head to
operate the eyes, also the arms and legs are removable.

yours hopefully June.