I found by accident a place with a good bit of discussion about words. Well worth checking out.

http://www.alt-usage-english.org/ucle/ucle9.html

Don't think I've heard of this one, Dr. Bill:
parafango (a mixture of mud and paraffin).
What would one use a mixture of mud and paraffin for??

bill! how remiss of you not to point out that this very URL has short discussions pertaining to "pear-shaped" and all those billions (or is it milliards) of words for snow.

(a related link is Mark Israel's FAQ; I don't remember if this has ever been cited here, but it carries quite a cachet of it's own and has particularly interesting sections on usage and word origins, many of which have been touched on here.)

http://www.english-usage.com/faq.html

I note with some interest that the article on words for mud in English outnumbering words for snow in Eskimo lists aput and gana as roots for snow on the ground and falling snow, respectively. Does this leave us back with no generic word for snow in Eskimo?

Dear Jackie: I think "parafango" would be what you call "modeling clay".

I also seem t recall name "plasticene". I couldn't find "plasticene" on Internet, but did find ad for a massage parlor offering: specializes in body therapies such as body scrubs,
parafango, mud treatment facials, massage, waxing, laser hair removal, and micro-derm abrasion.

On a second search I found:Notebook
... Nonhardening Modeling Clay / Plasticene or Plastilene.
Probably the most widely used of the three ...
http://www.noteaccess.com/MATERIALS/Matplasticene.htm