Alloy rims Very rough to the touch

I started a thread elsewhere but I've more info and THIS forum is probably the correct place for it.

Rear wheels are fine, front are in need of serious help. Inside the spokes they are black with brake dust, but wait there's more:

inside the spokes there are many areas that are raised maybe as much as a millimeter. Irregular areas, and Very rough to the touch, and don't want to be just scraped off.

I am no expert but I think these rims are way beyond cleaning; maybe even beyond "simple" polishing. What can I do? Should I take a Dremel tool to it? A sheet metal grinder? A sledgehammer perhaps?

The pic below is what they Should look like (back ones are like this). 1995 530i