Buy the cover caps from the dealer, $30 and your problem is 'out of sight, out of mind'.

 

5% vinegar which is acetic acid (available at any grocery store)will take that white oxidation/Corrosion off of chrome without damaging the chrome. I used a Q tip, it may need to soak for a while depending on how bad it is. From what I've read on other forums the stock bolt is not stainless and the oxidation is caused by the electrical charge of the bike.
This is time consuming so would suggest replacing the bolts with a polished stainless, I got a motor kit set for my 2011 Streetglide for $100 or less from alloybotz.com, so you don't have to do it twice. By the way when you replace the bolts be sure to use anti-seize and use an inch pound torque wrench.