Is that a good idea we have smokers in the house and the fins look smoke layered.

Thanks will try the vinegar was asking to make sure before I attempt

I have had to do this a few times in the past when I lived with smokers.  Alcohol never really did a good job since youre tryingto remove an oily tar. I found that hot very soapy water (use Dawn) and let it soak for about 20 min then use the hand srayer on the sink, if you have one. If not then use the shower and blast the crap out of it.
 
 let it dry and done.
 
 
 
 
 

I've used acetone before and it worked well, may just want to clean off any residue after the fact.

use ArtiClean, the same people who make AS5 thermal compound, it has been great for me. plus it is only about 5 bucks and you can get it at radio shack.

I use ArctiClean to clean contact surfaces.  I dont see why acetone wouldnt work, it has a low flashpoint and it should dry residue free.