removing tar from ivory

[A440A@AOL.COM]

<< Roof tar has made its way onto the relatively new one-piece ivories on a 
client's piano.  Does anyone know a safe way to remove the tar which won't 
alter the ivory?   >>

The petroleum based carrier has probably worked its way into the ivory 
already, but to minimize further damage, DONT use a solvent at first. 
mechanically scrape the tar off, and then with a single edge razor, scrape 
until the ivory is white, if possible.  Sand with 400, then 600, then polish 
to match the neighbors. 
    There may be stains still left after all of this. If so, it is possible 
that an acetone dampened rag will wick the remainder back out of the ivory.  
If you start with a solvent, it will send the stain deeper into the keytop. 
Good luck, 
Ed Foote RPT