Buy a bulk tub of vinegar and a plasterers tub and sling your parts in there? Ive just tried it on a couple of engine mounts and it works MINT

Gonna try an exhaust manifold over the weekend too, will stick some before and after pics up too

I tried a few small drops on an old inlet manifold (cast aluminium) and it left it all day without any issues too, though Im going to do a proper test on that before I go dissolving my nice expensive throttle bodies

Shamelessly stole the idea from here

Home made parts washer for a tenner