Not sure if this will work, YMMV, all the usual disclaimers.
1. Ozium aerosol. It's the hospital smell. It kills the odor causing bacterium or particulate. Not sure if it's plastic safe.... I can vouch for its effectiveness, my mother used it to get RID of her colostomy bag odor. Not mask it, get RID of it.
--Shane
KD6VXI
Ozium is working on the wretched chain-smokers' chair here. Sprayed deep into it, repeated weekly.
Was an ozone generator tried? For a radio, maybe putting it with a generator in a 30x24x24 box for a day? The consumer units are known as " Living Air Purifier, Mountain Air or Fresh Air." brands. Beware they are not to be used constantly, except on very low, as ozone is harmful in concentrations. They also cost a fortune but can be borrowed or bought used.