Is this petrified wood

[Nitra]

Found this in my grandmas yard, 20 miles south of Springfield MO. If this is petrified wood, how should I properly clean it? Thank you 

[Rockwood]

It's hard to be certain from this photo, but it doesn't look like wood to me now.

If you can give us a better look it might help. It does look fossilish in a way.