From the looks of it, I would say you could have got those wheels to at least 80-90% back to new. Before going for the harshest chemicals dig deep for a bit of patience
. I know its the road less traveled but it pays in the long run. That brake dust build up has taken YEARS to accumulate, NO magic product will sort it out with a quick wipe.
My process would have been:
Step 1 - Wash thoroughly with a decent mag cleaner and brush. If its acid based, don't leave on the wheel for more that a minute. Like Onyx mentioned, read the instructions.
Step 2 - If you see that step is removing the brake dust then repeat until completely satisfied. IF not, move onto step three.
Step 3 - Try loosening up the dirt with a bit of tar remover. Let it sit on the contamination for a bit and then agitate with brush. Repeat if it works for you until clean, else move onto step 4
Step 4 - Use detail clay plus lube on the contamination and see if that picks up any dirt. Again, if that works for you, keep repeating until completely clean.
Generally these 4 steps covers 90% of wheel contamination but theres always the EXTREME cases.
In extreme cases wet-sanding is the LAST resort. This is the point where you have decided already that you will refurbish the wheels, so if you really mess up, you already prepared to pay to get it restored !
i sprayed the oven cleaner on and immediately cleaned the excess off... it left "dry" marks.. all the more reason to paint them.. and seeing as i now beggered the paint up on the one rim i had a go at that **** with the steelwool... it takes vark long but it comes off, but so does the paint 
