Another product that works wonders and is super cheap and lasts forever since you only use a little bit. Wood bleach from Sherwin Williams. It contains oxalic acid and has been an old skool rust remover for chrome parts.
I removed 22 years of rust off of every piece of chrome, including the spoked wheels on my '82 CB750k project bike. Absolutely amazing product.
On non chrome like those bolts, I believe it would turn them darker in color (even black), but still does the job nicely.
http://sherwin.scene7.com/is/image/sw/paint_template-1?layer=comp&wid=189&fmt=jpeg&qlt=100,0&op_sharpen=0&resMode=sharp2&op_usm=0.0,0.0,0,0&iccEmbed=0&printRes=150&_tparam_layer_1_src=sw/SGCS01040164