im making my first sinew backed bow.How do i degrease osage or any other wood for that matter?

I just wipe it down with denatured  alcohol.
  Pappy

no denatured alcohol on hand, wondering about acetone would that work

Acetone will work just fine. Scrub it good.

thanks, all i need to hear...or read

Just plain old water too, keep after it till color doesn't come off on the rag.  I've used mineral spirits as well.  I've heard of folks using lye, a mild solution, then vinegar solution to neutralize.  Just let it dry thoroughly before you lay any hide glue.  And size the crap out of it, like three coats.  On the few sinew and raw hide jobs I did, I didn't find it required a great deal of degreasing.  You want a rough surface anyway, like with a 50 grit or more coarse paper.