preping wood question

I was given some pear wood that has a green powder on it, looks like some kind of algea.
I'm wondering if it ok to use, I can scrub it off with soap and water, but am
wondering if whatever it is could still be there unseen. The wood was from an
un-sprayed tree. Should I try to use it ? I still need to boil and bake it.
Just wodering if anybody else has come up with this.

Thanks
Edgars Dad