Sears Parts Stores used to sell a liquid called "chlorine dioxide", which is an oxidizing agent pretty good at removing smells without messing up colors. I prefer to use something like Clorox brand's OxyMagic spray (no chlorine, just peroxide based) or Woolite's carpet oxiding spray which also has a peroxide base.
The chlorine dioxide is supposed to be harmless, but there is some info on the internet that says you should use it with good ventilation and not expose yourself to the fumes for long.