what cleaner to use??

gonna try and clean up the frame of the '49 (front clip) and spray it with something like Rust Bullet (something that requires minimal prep) Anyhow it is pretty clean except for some gunk in the nooks and crannies I can't reach. What would be a good choice, laquer thinner, mineral spirits, acetone??? Probably gonna need alot, and hopefully cheap...Thanks-

 

I use oven cleaner on engines and frames to soften up old grease, followed by the pressure washer. It will eat paint, so be careful. overspray