My recently purchased 1150gs was much the same condition as yours, i wouldnt waste your time trying to clean old rusty bolts etc, just replace with stainless, its quite cheap to do , ive gone through most of mine and its cost me about £50 in stainless bolts, makes a big diffrence to the looks,, a word of caution tho dont put stainless into aluminium threads without coating in copaslip first,
Have a search round and find a local fastners supplier, buying of ebay or online for stainless is genrally a lot more expensive ,



. All the old tat is in the tub pictured