I've heard Mike Curotto say "rust never sleeps", but I don't fully understand this expression. Hmmmm I don't know what it means.
I've had great success soaking rusty parts overnight in a mixture of bleach and washing up detergent, but apparently it's dangerous to mix these two substances. Worked wonders for me though. The rust literally falls off in big chucks. Maybe don't try it if it's dangerous, but these are two household products that can be found under the sink if you don't want to go out and buy some rust removal products. Just my two cents. If it's dangerous you probably shouldn't mix the two, but I did it and I'm still here. :)