Fitting the stretchers

I guess these are bird's mouth joints.  Double bird's mouth joints.  Strangely enough, or it is to me, these 3x8's are really out of square.  I'm shying away from squaring them up for they have a lot of grit, tiny rocks, staples and nails in them.  I check them over and scrape with a cabinet scraper but I still don't want to run them through the jointer.
So the joinery takes some final fiddling with to get things matching up.