Actually there`s no way to remove the spots as the acid corroded itself through the anodized layer.
Restoring it to old condition is not easy. The anodized layer would need to be removed and that is usually done via sandbead blasting or etchant. Both ways I would not recommend as they are aggressive and can weaken the material. Glasbead blasting is probably the best way and then anodize again.
I guess I personally would look for a semi gloss clear coat, clean the spots and just paint them to prevent any oxidation.
If you take it to a shop that does anodize, they can strip it, and re-anodize the part. It will probably be more dull looking than it does now since the etchant to take off the anodize will also etch the aluminum underneath it.
If you want to polish it, then you can remove the anodize with off the shelf oven cleaner. Its pretty caustic, so wear glasses, gloves, and a lab apron. as with all chemical reactions, heat helps. The part will be a bit splotchy in appearance, but polishing it will take care of that.
Thats a lot of work for some little spots, but it might be worth it to you. You will have to get all new swingarm bearings while you are at it.
Cheers,
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.