My 16's have been sitting in my garage for about 8 months, and I was wondering if there were any tips or tricks that I could use to really clean them up.

When I use the plain old "car soap" all the brake dust residue doesn't seem to completely come off.

Any further help would be greatly appreciated.

 

Try a commercial wheel cleaner that you buy from the parts store, and repeat if necessary. I would not use anything more harsh than that.