Looking at cleaning up my 18' rims. Got a thick layer of caked on brake fluid that wont come off. Recently tried BlueMagic tire and rim cleaner but that did nothing... now Im thinking about using SOS ultra fine steel wool pads in conjunction with Simoniz wheel cleaner. Any thoughts from the community? I know you have to be careful when using steel wool pads on rims becasue they could scratch the hell out of them, but these are ultra fine so they should be safe. The auto detailing shop I used to work at used these pads in conjunction with a industrial grade wheel acid and it worked GREAT! I just wanted to see what you guys think before I go ahead and try it on these LR wheels.

Have you tried using something like brake parts cleaner and letting it soak? As in just spraying the heck out of the area, letting it sit for a few minutes, then see what can be wiped off. Also, I would think a plastic scraper with be safer than steel wool.

Magic eraser, the extra strenth kitchen kind. If that doesnt work then the finest of steel wool that you can get. Mr. Clean is amazing and it wont hurt your rims and should work great. I clean my rims with em every wash to get that brake build up off.

BlueMagic came with cloths and a plastic bristle brush - did not work.
I stand behind MagicEraser's - but failed to remove the brake dust from my rims. I believe ultra fine is the best you can get so Im gonna pick some up tomorrow at walmart lol.

About 2 months ago I cleaned all 4 rims with basic wheel acid, everything came out great and got all the yellowing off. Than about a month in a half ago my front passegner caliper burst and a large amount of brake fluid spewed out all over the tire and rim. Right in the middle of winter so I have not had a chance to remove it and its been sitting on the rim for about a month now. Its a thick layer.

I had a friend with some older alloys that had years of old brake dust built up on them...nothing was touching it, soaking with wheel cleaner, scrubbing with fine wool to the point it started to remove some of the finish in the test area and not removing the caked on dust.
Like you said, wheel cleaner is basically acidic. We picked up some muriatic acid and diluted it 50% or so.
Strong rubber kitchen gloves are a must, a tin can to hold the mixture and don't get a wiff of the stuff either! (don't get it on you..might want eye protection too)
Have a very sudsy soapy bucket of water to immediately get it off the wheel. You would not want to let it dry on the rim.
We washed the rim 3 times with the soapy water to ensure full removal all the acid.
It was a last resort for me, but did work... they look like new. Put a coat of light wax on after. If you are out of options...nasty job
I feel like I should insert the disclaimer here now...lol

I have used one of those cone shaped foam buffer wheels, from Mother's, if I remember right and some of their metal polish and that worked really well. After wards, I polished the wheels so dust won't stick to them.

That's the trick, getting something back on them AFTER cleaning. If you use Acid or heavy cleaners, you've opened the microscopic pores a bit and need to seal them again so those pores don't grab dirt next time. Polish or something like Mike said is important.

I've actually used a plastic bristle brush with coke before on my RX8 when I had it, and it worked great. Was a tip some "brothers" hanging around at oreillys told me they use to clean their big chrome rims instead of having to buy expensive cleaners.

On my Harley Wire Spoke wheels, I used AWESOME from the $1 store. One dollar, and it worked better than ALL the other cleaners I tried, even getting all the brake dust off. Also made the White Walls "White" again. Most other cleaners wouldn't do that, and the Awesome never caused my tires to dry out. It is the Standard Yellow version. Not the wheel or tire stuff, just standard. Works GREAT!