I appreciate the comments, not only is this my first attempt at weathering, it's my first build since returning to models last August. I'm hoping to achieve a 90+ year old car put together to drive and the drags on a budget and to get the proper patina and not to end up in exaggerated rust.
My 1st attempt on the trunk turned out better, I screwed it up trying to "fix" it, so purple pond. The firewall was a disaster at trying to be model correct, so I'm going with period correct for a hot rod find and an unknown firewall.
That was easy. I used a black wash, which I watered down and applied with a really wet brush. I then dabbed with a paper towel and allowed to dry. I think it left a good effect.