The problem is that you don;t really know what tye of paints you're dealing with. If you can, you want to find a solvent that dissolves the silver paint and leaves the original paint intact.

So, you might remove one of the anodized parts with paint and try different solvents. After you determine which solvent will remove the silver paint, you can try it on an inconspicuous location (like to BB shell) to determine of it will also remove the original paint. For example, if mineral spirits removes the silver paint, clean the underside of the BB of the silver paint. Then put a little mineral spirits on a rag and rub the original paint with the rag. If you get the original paint color on the rag, stop and try something else.

You might also try really fine (2000 grit) wet/dry sandpaper that is soaked in soapy water. That would take a while, but it might work.

Also detailer's clay (aka overspray clay) is even less abrasive and leaves a very smooth surface.

Good luck. It is a shame to see that careless paint job on a nice bike.