I have several bikes and use them more and more in bad weather. I have no problem with rust on the chain, but I am seeing little bits of rust in the various hex bolt heads on the bike. What can I use to remove this rust and how can I prevent it from happening again. Note I ride things like Ragbrai, so keeping out of the rain, or drying the bike right away is not an option.
Where possible, replace with stainless fasteners. Things like water bottle bracket bolts are readily available in stainless at a good hardware store.
But most fasteners on a good quality bike are stainless to begin with, so it may be that you're not seeing "rust" per se but rather a sort of corrosion that can form on stainless.
After cleaning I give the bolts a small squirt of WD40 followed by a good rub down.
This leaves a very fine film of oil that won't hold dirt but is just enough to stave off the rust if done regularly.
The spray also displaces (WD, water displacement, geddit?) any water left from cleaning in any little gaps.
Little bits of rust shouldn't hurt anything, but if you're getting lots of rust or it just drives you crazy you might consider spraying them down with a wax based lubricant or dry lube. Finish Line's Teflon dry lube might be a good option because it has a tendency to build up on chains, which means it goes on thick and may act as a barrier to oxidation. Boeshield's T9 may be another option though it goes on thinner than Finish Line's product. Of course these products aren't truly "dry" and you're going to be trading rust for dirt. If you wanted to get really crazy you could pack the heads with paraffin wax, but that seems over the top to me which brings me back to my first point that you probably shouldn't worry about it.
I like using marine grease in the hex "slot" itself. Just get a mini grease gun and some tubes of marine grease (both available from automotive shops), and then you can quickly apply little blobs of grease in each bolt head.
You'll end up with some grease on the ends of your hex wrenches whenever you make adjustments, but this way you know that your bolt heads won't clog with dirt or ice (or rust, which as others have noted usually does not meet destructive levels).
A mini grease gun is also what you use for maintaining Speedplay pedals.
You may have to do some searching to find the right sizes but you could go with stainless steel hardware. Buying them in small quantities can be expensive. I have had issues with some hardware that is countersunk. Conventional allenheads won't fit in the hole. Maybe that is why they call the brand "Specialized".