Take it off, on it, on it, use the BFH on it, then toss it in the trash. Are you serious? How to clean a roof rack? :-\
I tried several years ago. Took the rack and the runners all off. Mostly did it to apply Zaino to the beast, but while I had it all off I just used some good old fashioned elbow grease and wax - don't bother! It just keeps turning gray. If you remove it to apply a few good coats of wax underneath, go ahead, but otherwise, forget about it.
We send a lot of stuff to be anodized or powdercoated at the shop, not too expensive I think, but I'd have to check specific prices.
Toss it off a cliff. It isn't even as useful as that goo that forms around your mouth when you get hungry.
