Anyone know how to clean this type of stuff? As you can see the glass on it has yellowed. I think that it's most likely residue from smoking around them for many years. So I'm wondering if something like simple green would work. If you don't know what it is, it's a de-greaser and I know it worked great on my computers motherboard for removing the same stuff. However I'm not sure if it will ruin the figure or the paint on it. I have already tried washing it with soap and water and that didn't help, it got the dust off of it, but not the yellowing. Any thoughts on how to clean this up?