Now as far as the pin rash is is what I did. Remove the rust and then Painted the area with and aniline dye stain alcohol soluble that is mixed with shellac to a paint consistency. You can purchase the alcohol soluble stain in Ebony or Negro depending on the company. Any wood workers cat will have it. I buy mine at Lee Valley or Woodworkers supply. It comes in a 0ne once package in powder form that you mix with the alcohol and shellac. It coat about 10.00 for one once but will last you a long time. I mix 1/4 tsp with a tsp of alcohol until desolved and then add a enough shellac to make a paint. If not black enough add more powder. The little jar in the pics of tools is what I use to mix it in. Paint it on the bad spots with a good artist brush. Let cure for a day or two and then you can french polish over it to smooth it out adding more black shellac as needed.