I found bathtub liners at home depot for $6. They are flimsy plastic things used to protect bathtubs during remodels or new construction. I surround it with 16x8x8 concrete bricks (because I have a bunch handy) and put a liner of plastic ("painters plastic") in it. As long as your careful not to rip or tear anything it works fine. Although it does require a fair amount of solution.

I actually have one still set up that i'll try to take a picture of later that my brother used to soak the chrome header/exhaust from his Harley a week ago.